Affinage

AP1M1

AP-1 complex subunit mu-1 · UniProt Q9BXS5

Length
423 aa
Mass
48.6 kDa
Annotated
2026-06-09
50 papers in source corpus 28 papers cited in narrative 27 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 5/5 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

AP1M1 (mu1A/AP47) is the ubiquitously expressed medium-chain subunit of the AP-1A clathrin adaptor complex and is essential for AP-1 recruitment to the trans-Golgi network: in its absence the remaining gamma-adaptin fails to bind the TGN, mannose-6-phosphate receptors are rerouted to endosomes, and embryos die at midgestation (PMID:10811610). Within the assembled complex mu1A co-assembles with gamma-adaptin and the beta/beta' chains, and gamma-adaptin's N-terminal region directs membrane targeting and co-assembly with mu1A (PMID:7593184). mu1A executes cargo selection by binding tyrosine-based YxxΦ motifs, dileucine motifs, and even noncanonical basic motifs in the cytosolic tails of transmembrane cargo, thereby sorting kAE1 (PMID:20833140, PMID:22744004), CAR (PMID:22343291), CNNM4 (PMID:25449265), L-selectin (PMID:28235798), IRS-1 (PMID:23478262), and secretory-granule enzymes such as PAM-1 (PMID:25040637). Functionally it drives retrograde endosome-to-TGN recycling of MPRs (PMID:10811610, PMID:11792812), somatodendritic sorting of receptors in neurons where its loss reduces dendritic spines and synapses (PMID:22958822), biosynthetic basolateral delivery of select cargo (complementary to the epithelial-specific mu1B/AP-1B isoform that governs basolateral recycling) (PMID:10535737, PMID:10338135, PMID:22343291, PMID:22744004), secretory granule biogenesis in neuroendocrine cells (PMID:25040637), and endosome-to-lysosome transport, a step whose disruption prolongs endosomal residence of antisense oligonucleotides (PMID:40588516). The N-terminal ~70 residues of mu1A control AP-1 membrane-to-cytoplasm recycling independently of clathrin (PMID:17988225), regulated by the effector PREPL whose loss expands the TGN and impairs AP-1 recycling (PMID:23321636). mu1A is also hijacked by pathogens: HIV-1 Nef engages the mu1A tyrosine-binding site to downregulate MHC-I and to route CD4 to lysosomes via a gamma2/mu1A complex (PMID:22301137, PMID:27909244), and VZV ORF9p binds mu1A through a dileucine motif required for viral secondary envelopment (PMID:29793951). The function is deeply conserved, with the C. elegans ortholog unc-101 functionally interchangeable with mouse mu1A (PMID:8288128).

Mechanistic history

Synthesis pass · year-by-year structured walk · 15 steps
  1. 1991 Medium

    Establishing the molecular identity of mu1A was the prerequisite for assigning it to the AP-1 adaptor; cloning AP47 defined it as the conserved medium-chain subunit.

    Evidence cDNA cloning and comparative sequence analysis of mouse brain AP47 with a yeast homolog

    PMID:1761056

    Open questions at the time
    • Sequence identity alone did not establish the in vivo function
    • No cargo-recognition role demonstrated
  2. 1994 Medium

    Whether the adaptor function was conserved and physiologically important was tested genetically, showing the nematode ortholog unc-101 is functionally equivalent to mammalian mu1A.

    Evidence Genetic analysis and transgenic rescue in C. elegans

    PMID:8288128

    Open questions at the time
    • Did not define the molecular cargo or trafficking step
    • Vulval phenotype is pleiotropic
  3. 1995 Medium

    How mu1A is incorporated into AP-1 was mapped, showing gamma-adaptin's N-terminus drives membrane targeting and co-assembly with mu1A.

    Evidence Yeast two-hybrid and immunoprecipitation of chimeric adaptin constructs

    PMID:7593184

    Open questions at the time
    • Did not resolve which subunit recognizes cargo motifs
    • Assembly mapped in vitro, not in intact cells
  4. 2000 High

    The central question of whether mu1A is required for AP-1 function in vivo was answered: knockout abolished AP-1 membrane recruitment and disrupted MPR retrograde transport, making mu1A essential for development.

    Evidence Mouse gene knockout with cell fractionation, immunofluorescence and receptor trafficking assays

    PMID:10811610

    Open questions at the time
    • Did not identify the cargo-binding motifs directly
    • Embryonic lethality limited tissue-specific analysis
  5. 2001 High

    The distinct sub-cellular niches of mu1A versus the epithelial mu1B isoform were resolved, localizing mu1A-containing AP-1A to the TGN with furin and AP-1B to recycling endosomes.

    Evidence Immunofluorescence and immunoelectron microscopy of epitope-tagged subunits plus fractionation; quantitative MPR300 internalization assays in KO fibroblasts

    PMID:11157985 PMID:11792812

    Open questions at the time
    • Mechanism coupling AP-1A endosome-TGN transport to plasma-membrane recycling was indirect
    • Cargo-motif specificity not yet defined
  6. 2003 High

    The functional divergence of the two isoforms was sharpened by showing AP-1B, not mu1A-containing AP-1A, recruits exocyst subunits, tying mu1A to TGN/endosomal rather than exocytic delivery.

    Evidence Immunofluorescence, fractionation and co-localization with exocyst markers

    PMID:14581457

    Open questions at the time
    • Did not address how mu1A selects its own cargo
    • Single-lab observation
  7. 2007 Medium

    The basis of AP-1 cycling on and off membranes was localized to the mu1A N-terminal domain, which controls membrane-cytoplasm recycling independently of clathrin.

    Evidence mu2/mu1A domain chimeras with FRAP/live imaging and MPR trafficking readouts

    PMID:17988225

    Open questions at the time
    • Chimera approach, not endogenous mutation
    • Effector controlling N-terminal recycling unidentified at the time
  8. 2010 High

    Direct cargo recognition by mu1A was demonstrated biochemically for kAE1 via its YxxO motif, establishing mu1A as the motif-reading subunit for plasma-membrane delivery of this cargo.

    Evidence Yeast two-hybrid, co-IP, GST pulldown, affinity co-purification and PCA with siRNA localization readout

    PMID:20833140

    Open questions at the time
    • Polarized sorting route not yet placed
    • Performed largely in non-polarized HEK293T cells
  9. 2012 High

    Multiple studies converged to define mu1A as a YxxΦ/motif reader directing biosynthetic basolateral and neuronal somatodendritic sorting, and as a target of HIV-1 Nef for MHC-I downregulation.

    Evidence Motif mutagenesis, co-IP and knockdown for CAR (MDCK) and Nef (T cells); shRNA, live imaging and synapse morphology in hippocampal neurons; reciprocal Co-IP and in vivo tissue for kAE1

    PMID:22301137 PMID:22343291 PMID:22744004 PMID:22958822

    Open questions at the time
    • Structural basis of motif recognition not resolved in these studies
    • Functional partition between AP-1A and AP-1B cargo sets still being delineated
  10. 2013 Medium

    The regulatory and signal-recognition layer of mu1A was expanded: PREPL was identified as an N-terminal effector controlling AP-1 membrane binding, while mu1A/mu1B were shown to differ in sorting-signal specificity and mu1A to bind IRS-1 to control its localization and IGF signaling.

    Evidence Yeast two-hybrid, membrane-binding and TGN morphology assays in patient cells (PREPL); colocalization and cargo co-IP/mutagenesis (mu1A vs mu1B); motif mutagenesis with signaling/proliferation readouts (IRS-1)

    PMID:23321636 PMID:23478262 PMID:24229647

    Open questions at the time
    • Structural detail of PREPL-mu1A interface unresolved
    • Precise rule distinguishing mu1A vs mu1B signal preference incomplete
  11. 2014 Medium

    mu1A's role in TGN-to-basolateral cargo delivery and secretory-granule biogenesis was established, including isoform redundancy with mu1B for some cargo and direct binding to granule enzymes.

    Evidence Single/double siRNA knockdown and dileucine-motif mutagenesis (kAE1, CNNM4); shRNA, TEM, secretion assays and Y2H/co-IP for PAM-1 (AtT-20 cells)

    PMID:24698155 PMID:25040637 PMID:25449265

    Open questions at the time
    • Quantitative contribution of each adaptor in TGN-to-basolateral step not fully partitioned
    • Granule cargo selectivity mechanism incomplete
  12. 2016 Medium

    mu1A was assigned to a specific AP-1 variant (gamma2-containing) routing endosomal CD4 to lysosomes during Nef action, distinguishing it from the gamma1 complex.

    Evidence Selective siRNA depletion of mu1A vs gamma1 with CD4 trafficking assays in Nef-expressing cells

    PMID:27909244

    Open questions at the time
    • Endogenous (non-Nef) cargo of the gamma2/mu1A complex not defined
    • Single-lab epistasis
  13. 2017 Medium

    The cargo-recognition repertoire of mu1A was broadened beyond tyrosine/dileucine motifs by defining a novel basic motif in L-selectin bound by the mu1A C-terminal domain and switched off by phosphorylation.

    Evidence Peptide pulldown-MS, GST pulldown with domain mapping, co-IP, colocalization and molecular docking

    PMID:28235798

    Open questions at the time
    • No structure of the basic-motif/mu1A complex
    • Physiological retrograde route inferred from colocalization
  14. 2018 Medium

    Pathogen exploitation of mu1A was extended to VZV, where ORF9p binds mu1A via a dileucine motif required for viral secondary envelopment.

    Evidence Yeast two-hybrid, co-IP from infected cells and dileucine-mutant viral growth assays

    PMID:29793951

    Open questions at the time
    • Structural basis of ORF9p-mu1A binding unresolved
    • Host membrane source for envelopment not pinpointed
  15. 2025 High

    An unbiased screen placed mu1A at the endosome-to-lysosome transport step, with its loss prolonging endosomal residence and enhancing antisense-oligonucleotide activity.

    Evidence Genome-scale CRISPR/Cas9 knockout screen with ASO splice reporter and endosomal trafficking assays in vitro and in vivo

    PMID:40588516

    Open questions at the time
    • Molecular cargo mediating this lysosomal step not identified
    • Relationship to the gamma2/mu1A lysosomal route not directly tested

Open questions

Synthesis pass · forward-looking unresolved questions
  • How distinct mu1A-containing AP-1 variants (gamma1 vs gamma2) and cargo-motif classes are selected at each trafficking step, and the structural basis of noncanonical motif recognition, remain to be resolved.
  • No structure of mu1A bound to dileucine or basic cargo motifs in the corpus
  • Endogenous cargo set of the gamma2/mu1A lysosomal complex undefined
  • Mechanistic integration of PREPL-regulated recycling with cargo selection unresolved

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0060090 molecular adaptor activity 5 GO:0008289 lipid binding 1
Localization
GO:0005768 endosome 4 GO:0005794 Golgi apparatus 3 GO:0005829 cytosol 2 GO:0005886 plasma membrane 2
Pathway
R-HSA-5653656 Vesicle-mediated transport 4 R-HSA-9609507 Protein localization 4 R-HSA-1643685 Disease 3
Partners
AP1G1CXADRIRS1PAMPREPLSELLSLC4A1
Complex memberships
AP-1A clathrin adaptor complex

Evidence

Reading pass · 27 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2000 Targeted disruption of mouse mu1A-adaptin (AP1M1) causes embryonic lethality at day 13.5. In mu1A-deficient cells, the remaining AP-1 adaptins (gamma-adaptin) fail to bind to the TGN, demonstrating that mu1A is required for AP-1 membrane recruitment. Mannose 6-phosphate receptors (MPR46 and MPR300) are rerouted to endosomes at the expense of the TGN, and MPR46 fails to recycle back from endosomes to the TGN, establishing AP-1/mu1A as required for retrograde endosome-to-TGN transport. Gene knockout (targeted disruption), cell fractionation, immunofluorescence microscopy, receptor trafficking assays The EMBO journal High 10811610
1999 mu1A (AP1M1) is the ubiquitous mu1 subunit of the AP-1 clathrin adaptor complex (AP-1A), whereas the epithelial-specific isoform mu1B forms a distinct AP-1B complex. Stable expression of mu1B (not mu1A) in LLC-PK1 cells selectively restores basolateral targeting of membrane proteins, demonstrating that mu1A-containing AP-1A does not mediate basolateral sorting in epithelial cells. Stable transfection, immunofluorescence, domain-specific protein targeting assays in polarized epithelial cells Cell High 10338135 10535737
2001 AP-1A (mu1A-containing complex) localizes to the TGN and colocalizes with furin, whereas AP-1B localizes to recycling endosomes, as determined by immunofluorescence and immunoelectron microscopy of epitope-tagged mu1 subunits. AP-1A and AP-1B occupy distinct subdomains of the perinuclear region and interact differentially with clathrin-coated buds. Immunofluorescence microscopy, immunoelectron microscopy, subcellular fractionation, epitope-tagged subunit expression The Journal of cell biology High 11157985
2003 AP-1A (mu1A) and AP-1B define physically distinct membrane domains; AP-1B (but not AP-1A) enhances recruitment of exocyst subunits Sec8 and Exo70 to recycling endosome-proximal membranes, linking mu1A-containing AP-1A specifically to TGN/endosomal transport rather than basolateral exocytic delivery. Immunofluorescence, cell fractionation, co-localization analysis with exocyst subunit markers The Journal of cell biology High 14581457
2001 In mu1A-adaptin-deficient fibroblasts, the internalization rate of MPR300 is increased 7-fold without an increase in steady-state plasma membrane levels. More MPR300 is found in clathrin-coated pits at the plasma membrane, while all intracellular receptors reside in endosomes in equilibrium with the plasma membrane, indicating that AP-1-mediated transport from endosomes to TGN indirectly controls MPR300 recycling between plasma membrane and endosomes. Radioligand internalization assays, immunoelectron microscopy, receptor trafficking in mu1A-KO fibroblasts Journal of cell science High 11792812
2012 The mu1A subunit of AP-1 mediates somatodendritic sorting of transmembrane receptors in rat hippocampal neurons by recognizing sorting signals within the cytosolic domains of the proteins. AP-1/mu1A functions in conjunction with clathrin in the neuronal soma to exclude somatodendritic proteins from axonal transport carriers. Perturbation of this process reduces dendritic spine morphology and synapse number. shRNA knockdown, live-cell imaging, immunofluorescence, spine/synapse morphology assays in primary hippocampal neurons Neuron High 22958822
2012 The YxxΦ motif of the coxsackie and adenovirus receptor (CAR) directly interacts with a conserved pocket in mu1A of AP-1A, and this interaction is required for biosynthetic sorting of CAR to the basolateral surface. Knockdown of AP-1A (mu1A) impairs biosynthetic sorting of CAR, complementary to the role of AP-1B in basolateral recycling. Mutational analysis of YxxΦ motif, co-immunoprecipitation, siRNA knockdown, domain-specific trafficking assays in polarized MDCK cells Proceedings of the National Academy of Sciences of the United States of America High 22343291
2013 mu1A and mu1B largely colocalize with both TGN and recycling endosome markers, and with basolateral cargoes in both biosynthetic and endocytic-recycling routes. The two isoforms differ in signal-recognition specificity: mu1B preferentially binds a subset of basolateral sorting signals not recognized by mu1A, expanding the repertoire of AP-1 cargo recognition. Improved immunofluorescence colocalization, co-immunoprecipitation of cargo-adaptor interactions, mutagenesis of sorting signals Developmental cell High 24229647
2007 The N-terminal 70 amino acids of mu1A regulate AP-1 membrane-to-cytoplasm recycling. Chimeric AP-1* complexes containing a mu2/mu1A N-terminal domain showed slowed recycling kinetics and missorting of mannose-6-phosphate receptors, demonstrating that the mu1A N-terminal domain controls AP-1 recycling between membranes and cytoplasm independently of clathrin. Domain chimera construction, FRAP/live-cell imaging of AP-1 recycling kinetics, MPR trafficking assays in cells expressing chimeric adaptins Traffic (Copenhagen, Denmark) Medium 17988225
2013 The cytoplasmic prolyl-oligopeptidase-like protein PREPL interacts with the N-terminal domain of mu1A identified by yeast two-hybrid screen. PREPL overexpression reduces AP-1 membrane binding; reduced PREPL expression increases membrane binding and impairs AP-1 recycling. PREPL-deficient cells have an expanded TGN rescued by PREPL re-expression, defining PREPL as an AP-1 effector that regulates mu1A-dependent membrane binding. Yeast two-hybrid, AP-1 membrane-binding assays, TGN morphology quantification in patient cell lines and PREPL overexpression/knockdown cells Journal of cell science Medium 23321636
1995 Subunit interactions within AP-1 were mapped: gamma-adaptin and AP47 (mu1A) interact; the NH2-terminal region of gamma-adaptin (aa ~130–330/350) determines membrane targeting and co-assembly with AP47 and AP19. Beta/beta'-adaptins interact with AP50/AP47, but beta/beta'-adaptins are not involved in targeting. These results establish that AP47 subunit interactions contribute to AP-1 complex assembly and TGN targeting. Yeast two-hybrid system, chimeric adaptin constructs, immunoprecipitation The Journal of cell biology Medium 7593184
1994 The C. elegans unc-101 gene encodes a homolog of mammalian AP47 (mu1A). Mouse AP47 and nematode UNC-101 are functionally equivalent as demonstrated in transgenic nematodes, establishing cross-species conservation of the mu1A clathrin-adaptor function. Loss of unc-101/mu1A function causes pleiotropic developmental defects including misregulation of vulval differentiation. Genetic analysis, cDNA cloning, transgenic rescue assay in C. elegans Genes & development Medium 8288128
2010 AP-1 mu1A directly interacts with the C-terminal cytoplasmic domain of kidney anion exchanger 1 (kAE1) via the YXXØ motif Y904DEV907. siRNA-mediated knockdown of AP-1 mu1A in HEK293T cells decreases membrane localization of kAE1 and increases its intracellular accumulation, demonstrating that AP-1 mu1A is required for kAE1 trafficking to the plasma membrane. Yeast two-hybrid, co-immunoprecipitation, affinity co-purification, GST pulldown, YFP-based protein fragment complementation assay, siRNA knockdown with localization readout Biochemical and biophysical research communications High 20833140
2012 mu1A (and to a lesser extent mu1B) are required for kAE1 trafficking to the basolateral plasma membrane; knockdown of mu1A causes kAE1 to fail to reach the plasma membrane and undergo lysosomal degradation. Reciprocal co-immunoprecipitation confirmed mu1A–kAE1 interaction in epithelial cells and in mouse kidney extracts in vivo. Newly synthesized kAE1 does not traffic through recycling endosomes, suggesting AP-1A (not AP-1B) is the primary mediator of newly synthesized kAE1 delivery. Reciprocal co-immunoprecipitation in epithelial cells and mouse kidney extract, siRNA knockdown, immunofluorescence trafficking assays American journal of physiology. Cell physiology High 22744004
2014 AP-1 mu1A (AP-1A) is required for kAE1 sorting from the TGN to the basolateral membrane; RNA interference of AP-1 mu1A (but not mu1B, PKD1, or PKD2) blocks kAE1 intracellular sorting and trafficking. AP-3 mu1 and AP-4 mu1 and clathrin are also required, placing AP-1A/mu1A in the TGN-to-basolateral trafficking pathway for kAE1. siRNA knockdown, co-immunoprecipitation, YFP-PCA, immunofluorescence in polarized and non-polarized kidney cells and human kidney tissue Traffic (Copenhagen, Denmark) Medium 24698155
2014 AP-1A (mu1A subunit) is required for normal secretory granule (SG) biogenesis in AtT-20 corticotrope cells. Twofold reduction of mu1A decreases TGN cisternae and immature SGs, misroutes carboxypeptidase D (CPD) and peptidylglycine alpha-amidating monooxygenase-1 (PAM-1) from their normal immature SG pathway, and halves stimulated secretion. Yeast two-hybrid and co-immunoprecipitation demonstrated direct interaction between PAM-1 cytosolic domain and AP-1A (mu1A). shRNA knockdown, secretion assays, morphological analysis (TEM), yeast two-hybrid, co-immunoprecipitation, metabolic labeling Traffic (Copenhagen, Denmark) Medium 25040637
2013 IRS-1 associates with mu1A of AP-1A via three YXXØ motifs. Wild-type IRS-1 localizes to peripheral vesicular structures dependent on AP-1; IRS-1 mutants lacking YXXØ motifs are mislocalized to mannose-6-phosphate receptor-positive structures, impairing IGF-I-induced tyrosine phosphorylation, PI3-kinase association, and cell proliferation. Co-immunoprecipitation, mutagenesis of YXXØ motifs, immunofluorescence localization, siRNA knockdown, IGF-I signaling assays (phosphorylation, PI3K association), proliferation assays Molecular and cellular biology Medium 23478262
2016 mu1A (AP1M1) subunit depletion, but not gamma1 (AP1G1) depletion, prevents HIV-1 Nef-mediated lysosomal degradation of CD4, causing internalized CD4 to accumulate in early endosomes. This places mu1A in the AP-1 variant containing gamma2 (AP1G2) that routes endosomal cargo to lysosomes, distinct from the gamma1-containing AP-1 complex. siRNA knockdown, immunofluorescence, CD4 surface/intracellular trafficking assays in Nef-expressing cells Journal of cell science Medium 27909244
2017 The cytoplasmic tail of L-selectin directly binds the C-terminal domain of mu1A via a novel basic motif (three dibasic residue clusters: 356RR357, 359KK360, 362KK363) and a distal 369DD370 element. Phosphorylation of the L-selectin tail abrogates mu1A binding. L-selectin colocalizes with AP-1 at the TGN, suggesting constitutive AP-1/mu1A-mediated retrograde transport of L-selectin. Peptide pulldown with mass spectrometry, GST-pulldown with domain mapping, co-immunoprecipitation, immunofluorescence colocalization, molecular docking The Journal of biological chemistry Medium 28235798
2018 VZV ORF9p (tegument protein) interacts with AP1M1 (mu1 subunit of AP-1). Disruption of the ORF9p dileucine motif (L231A) abolishes AP-1 binding and strongly impairs viral growth by preventing efficient secondary envelopment, demonstrating that AP-1/mu1A interaction with ORF9p is required for VZV secondary envelopment. Yeast two-hybrid screen, co-immunoprecipitation from infected cells, viral mutant generation and growth assays Journal of virology Medium 29793951
2012 A noncanonical tripartite hydrophobic motif (Trp13/Val16/Met20) in the N-terminus of HIV-1 Nef functions as a mu1A-binding motif, interacting with the tyrosine motif-binding site of mu1A, and is required for Nef-mediated MHC-I downregulation in T lymphocytes. Mutagenesis of Nef N-terminal motif, co-immunoprecipitation/binding assays with mu1A, functional MHC-I downregulation assays Journal of virology Medium 22301137
2014 Basolateral sorting of the Mg2+ transporter CNNM4 requires both AP-1A (mu1A) and AP-1B; single knockdown of mu1B alone does not affect basolateral localization, but simultaneous knockdown of mu1A abrogates it. Three dileucine motifs in CNNM4 are required for basolateral sorting and for interaction with mu1A and mu1B. siRNA knockdown (single and double), mutational analysis of dileucine motifs, immunofluorescence localization in MDCK cells Biochemical and biophysical research communications Medium 25449265
1991 Mouse brain AP47 (mu1A) was cloned and sequenced. It is closely related to AP50 (mu2), and a yeast homolog (YAP54) was identified with striking homology to AP47, suggesting AP47/mu1A is the medium chain subunit of AP-1 in both mammals and yeast, with a conserved domain organization. cDNA cloning, sequence analysis, comparative genomics, domain modeling European journal of biochemistry Medium 1761056
2025 CRISPR/Cas9 knockout of AP1M1 strongly increases anti-sense oligonucleotide (ASO) activity by delaying endosome-to-lysosome transport both in vitro and in vivo, prolonging ASO residence time in the endosomal system and increasing likelihood of ASO endosomal escape. This places AP1M1 mechanistically at the endosome-to-lysosome transport step. Unbiased CRISPR/Cas9 knockout screen, ASO splice reporter assay, endosomal trafficking assays in vitro and in vivo Nature communications High 40588516
2019 HBV infection upregulates AP1M1 expression in HepG2.215 liver cancer cells via the JNK signaling pathway. Silencing AP1M1 suppresses proliferation of HBV-expressing cells while overexpression promotes proliferation. Increased AP1M1 enhances phosphorylation of AKT (protein kinase B), placing AP1M1 downstream of JNK and upstream of AKT in HBV-driven proliferation. siRNA knockdown, overexpression, JNK pathway inhibition, Western blot for AKT phosphorylation, cell proliferation assays Oncology letters Low 31289517
2006 Both mu1A and mu1B isoforms of AP-1 are co-expressed in melanocytes and keratinocytes. Expression of mu1B (but not mu1A) restores sorting of the melanosome structural protein Pmel17 to the plasma membrane in cells lacking mu1B, indicating that mu1A-containing AP-1A and mu1B-containing AP-1B define distinct sorting routes for melanosome cargo. Real-time PCR, immunolabeling, in situ hybridization, transfection with mu1A or mu1B isoforms, Pmel17 trafficking assays Journal of cell science Medium 16492709
2015 Reduced AP-1 function (via mu1A subunit knockdown) alters endocytic trafficking of PAM-1 (peptidylglycine alpha-amidating monooxygenase), causing PAM-1 accumulation on the cell surface. Co-immunoprecipitation demonstrates that a small fraction of PAM and Atp7a interact, suggesting copper transfer between the two proteins in shared subcellular compartments is disrupted when AP-1/mu1A levels are reduced. shRNA knockdown of mu1A, immunofluorescence, surface biotinylation, co-immunoprecipitation The Journal of biological chemistry Medium 26170456

Source papers

Stage 0 corpus · 50 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2006 An optimized grapevine RNA isolation procedure and statistical determination of reference genes for real-time RT-PCR during berry development. BMC plant biology 577 17105665
1999 A novel clathrin adaptor complex mediates basolateral targeting in polarized epithelial cells. Cell 432 10535737
2000 mu1A-adaptin-deficient mice: lethality, loss of AP-1 binding and rerouting of mannose 6-phosphate receptors. The EMBO journal 369 10811610
1999 Mu1B, a novel adaptor medium chain expressed in polarized epithelial cells. FEBS letters 212 10338135
2001 Distribution and function of AP-1 clathrin adaptor complexes in polarized epithelial cells. The Journal of cell biology 208 11157985
2003 The AP-1A and AP-1B clathrin adaptor complexes define biochemically and functionally distinct membrane domains. The Journal of cell biology 169 14581457
1995 Targeting signals and subunit interactions in coated vesicle adaptor complexes. The Journal of cell biology 135 7593184
1994 unc-101, a gene required for many aspects of Caenorhabditis elegans development and behavior, encodes a clathrin-associated protein. Genes & development 111 8288128
1985 Differential control of U1 small nuclear RNA expression during mouse development. Science (New York, N.Y.) 96 2412294
2012 Signal-mediated, AP-1/clathrin-dependent sorting of transmembrane receptors to the somatodendritic domain of hippocampal neurons. Neuron 95 22958822
1991 Heterologous expression of the allelic variant mu-class glutathione transferases mu and psi. The Biochemical journal 88 2049077
1994 Two rat homologs of clathrin-associated adaptor proteins. Gene 70 8076832
2012 Basolateral sorting of the coxsackie and adenovirus receptor through interaction of a canonical YXXPhi motif with the clathrin adaptors AP-1A and AP-1B. Proceedings of the National Academy of Sciences of the United States of America 66 22343291
2013 The adaptor protein-1 μ1B subunit expands the repertoire of basolateral sorting signal recognition in epithelial cells. Developmental cell 63 24229647
2001 Mu 1A deficiency induces a profound increase in MPR300/IGF-II receptor internalization rate. Journal of cell science 59 11792812
1991 The medium chains of the mammalian clathrin-associated proteins have a homolog in yeast. European journal of biochemistry 53 1761056
2006 Sorting of Pmel17 to melanosomes through the plasma membrane by AP1 and AP2: evidence for the polarized nature of melanocytes. Journal of cell science 46 16492709
2015 Postharvest application of a novel chitinase cloned from Metschnikowia fructicola and overexpressed in Pichia pastoris to control brown rot of peaches. International journal of food microbiology 38 25632799
2016 CD4 downregulation by the HIV-1 protein Nef reveals distinct roles for the γ1 and γ2 subunits of the AP-1 complex in protein trafficking. Journal of cell science 33 27909244
2014 AP-1A controls secretory granule biogenesis and trafficking of membrane secretory granule proteins. Traffic (Copenhagen, Denmark) 28 25040637
2013 The AP-1 complex regulates intracellular localization of insulin receptor substrate 1, which is required for insulin-like growth factor I-dependent cell proliferation. Molecular and cellular biology 23 23478262
2013 Trans-Golgi network morphology and sorting is regulated by prolyl-oligopeptidase-like protein PREPL and the AP-1 complex subunit μ1A. Journal of cell science 22 23321636
1997 Identification of two new mu-adaptin-related proteins, mu-ARP1 and mu-ARP2. FEBS letters 22 9013859
2010 Human kidney anion exchanger 1 interacts with adaptor-related protein complex 1 μ1A (AP-1 mu1A). Biochemical and biophysical research communications 20 20833140
1988 The embryonic and adult mouse U1 snRNA genes map to different chromosomal loci. Somatic cell and molecular genetics 19 2894719
2010 Characterization of the AP-1 μ1A and μ1B adaptins in zebrafish (Danio rerio). Developmental dynamics : an official publication of the American Association of Anatomists 18 20652956
2018 Varicella-Zoster Virus ORF9p Binding to Cellular Adaptor Protein Complex 1 Is Important for Viral Infectivity. Journal of virology 16 29793951
2012 Adaptor protein 1 complexes regulate intracellular trafficking of the kidney anion exchanger 1 in epithelial cells. American journal of physiology. Cell physiology 16 22744004
2022 Discovery proteomics reveals potential protein signature associated with malignant phenotype acquisition in pleomorphic adenoma. Oral diseases 12 34902207
2007 AP-1 membrane-cytoplasm recycling regulated by mu1A-adaptin. Traffic (Copenhagen, Denmark) 12 17988225
2019 Proteomics characterisation of central nervous system metastasis biomarkers in triple negative breast cancer. Ecancermedicalscience 11 30792808
2019 HBV upregulates AP-1 complex subunit mu-1 expression via the JNK pathway to promote proliferation of liver cancer cells. Oncology letters 11 31289517
2014 Basolateral sorting of the Mg²⁺ transporter CNNM4 requires interaction with AP-1A and AP-1B. Biochemical and biophysical research communications 11 25449265
2017 The cytoplasmic tail of L-selectin interacts with the adaptor-protein complex AP-1 subunit μ1A via a novel basic binding motif. The Journal of biological chemistry 10 28235798
2015 Adaptor Protein-1 Complex Affects the Endocytic Trafficking and Function of Peptidylglycine α-Amidating Monooxygenase, a Luminal Cuproenzyme. The Journal of biological chemistry 10 26170456
2011 Human kidney anion exchanger 1 interacts with kinesin family member 3B (KIF3B). Biochemical and biophysical research communications 10 21871436
2001 Identification of clathrin-adaptor medium chains in Dictyostelium discoideum: differential expression during development. Gene 10 11179674
2013 Analysis of three μ1-AP1 subunits during zebrafish development. Developmental dynamics : an official publication of the American Association of Anatomists 9 24123392
2012 A noncanonical mu-1A-binding motif in the N terminus of HIV-1 Nef determines its ability to downregulate major histocompatibility complex class I in T lymphocytes. Journal of virology 9 22301137
1999 Cloning, mapping and tissue-specific expression of Drosophila clathrin-associated protein AP50 gene. Gene 9 10375633
2014 Role of adaptor proteins and clathrin in the trafficking of human kidney anion exchanger 1 (kAE1) to the cell surface. Traffic (Copenhagen, Denmark) 8 24698155
1998 Cloning, expression pattern, and chromosomal assignment to 16q23 of the human gamma-adaptin gene (ADTG). Genomics 7 9653655
2016 Comparative Genomic Analysis of Enterovirus 71 Revealed Six New Potential Neurovirulence-associated Sites. Biomedical and environmental sciences : BES 6 27927278
2005 Identification of T-cell epitopes on U1A protein in MRL/lpr mice: double-negative T cells are the major responsive cells. Immunology 6 15885135
2023 Deficiency of AP1 Complex Ap1g1 in Zebrafish Model Led to Perturbation of Neurodevelopment, Female and Male Fertility; New Insight to Understand Adaptinopathies. International journal of molecular sciences 5 37108275
2022 Adaptor complex-mediated trafficking of Newcastle disease virus fusion protein is regulated by the YLMY motif of its cytoplasmic tail. Virulence 5 36258290
2025 A CRISPR/Cas9 screen reveals proteins at the endosome-Golgi interface that modulate cellular anti-sense oligonucleotide activity. Nature communications 4 40588516
1999 Genomic structure and chromosome mapping of the genes encoding clathrin-associated adaptor medium chains mu1A (Ap1m1) and mu1B (Ap1m2). Cytogenetics and cell genetics 4 10640811
2025 Deciphering the molecular tapestry of schizophrenia: integrating transcriptomics, neuroimaging, and clinical data for precision medicine. Translational psychiatry 1 41271614
1995 Neuropeptide-like immunoreactivities and carboxypeptide H activity associated with bovine brain clathrin coated vesicles. Neuropeptides 0 7666953

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