| 1996 |
The ALG3 gene of Saccharomyces cerevisiae encodes a potential ER-transmembrane protein of 458 amino acids (53 kDa) with a C-terminal KKXX-retrieval sequence; its inactivation results in accumulation of lipid-linked Man5GlcNAc2 and transfer of Endo H-resistant (underglycosylated) carbohydrates to protein by the oligosaccharyltransferase complex, establishing ALG3 as required for dolichol-linked oligosaccharide biosynthesis beyond Man5GlcNAc2. |
Complementation cloning of alg3 temperature-sensitive mutant; gene disruption; biochemical analysis of lipid-linked oligosaccharides and secretory protein glycosylation |
Glycobiology |
High |
8842708
|
| 2001 |
ALG3 encodes the Dol-P-Man:Man5GlcNAc2-PP-Dol mannosyltransferase itself (not an accessory protein): immunoprecipitation of an HA-tagged ALG3 fusion selectively co-precipitated mannosyltransferase activity converting Man5GlcNAc2-PP-Dol to Man6GlcNAc2-PP-Dol from detergent-solubilized yeast membranes, and the initial Man5→Man6 reaction is metal-ion independent whereas further elongation requires Mn2+. |
In vitro mannosyltransferase assay with [3H]Man5GlcNAc2-PP-Dol substrate; immunoprecipitation of HA-tagged ALG3 fusion protein to co-precipitate enzymatic activity |
Biological chemistry |
High |
11308030
|
| 1991 |
Structural analysis of oligosaccharides from alg3,sec18 yeast by 1H NMR established that the alg3 mutant accumulates Man5GlcNAc2-PP-dolichol due to a defective alpha-1,3-mannosyltransferase required for the next elongation step, and that the transferred Man5GlcNAc2 structure is Man-alpha1,2Man-alpha1,2Man-alpha1,3(Man-alpha1,6)Man-beta1,4GlcNAc-beta1,4GlcNAc. |
1H NMR spectroscopy of oligosaccharides released from ER-restricted invertase in alg3,sec18 yeast; peptide-N-glycosidase F and Endo H digestion |
The Journal of biological chemistry |
High |
2005096
|
| 1993 |
In the alg3,sec18,gls1 triple mutant, the majority (>75%) of ER N-linked glycosylation occurs by transfer of Man5GlcNAc2 without prior addition of the 3 glucoses normally present on the lipid-linked precursor; 2D DQF-COSY 1H NMR revealed Glc3Man5GlcNAc2 and Man8GlcNAc2 as the glucosylated species, demonstrating that the alg3 yeast still glucosylates both Man5 and Man9 precursors. |
500-MHz 2D DQF-COSY 1H NMR spectroscopy; Endo H and PNGase F digestion; Bio-Gel P-4 oligosaccharide sizing of invertase glycans from alg3,sec18,gls1 yeast |
The Journal of biological chemistry |
High |
8505333
|
| 1993 |
In the delta-och1 mnn1 alg3 triple mutant of S. cerevisiae, N-linked oligosaccharides accumulated as Man5GlcNAc2 and Man8GlcNAc2 in total cell mannoprotein, confirming the lack of outer chain addition to the incomplete core-like oligosaccharide and the leaky phenotype of the alg3 mutation; this established that the ALG3-dependent Man8GlcNAc2 core is the substrate for OCH1-initiated alpha-1,6-polymannose outer chain addition. |
Structural analysis of pyridylaminated neutral oligosaccharides from purified periplasmic invertase by hydrazinolysis, N-acetylation, and chromatography |
The Journal of biological chemistry |
High |
8253757
|
| 2004 |
The Pichia pastoris ALG3 homolog encodes the enzyme converting Man5GlcNAc2-Dol-PP to Man6GlcNAc2-Dol-PP; deletion in an och1 background leads to secretion of Man5GlcNAc2-containing glycoproteins trimmable by alpha-1,2-mannosidase, plus additional larger glycans (Hex6-Hex12GlcNAc2) resistant to mannosidase digestion, revealing divergent Golgi processing relative to S. cerevisiae alg3. |
Gene deletion (alg3Δ) in P. pastoris; glycan profiling by mass spectrometry; in vitro alpha-1,2-mannosidase digestion of secreted glycoproteins |
Glycobiology |
High |
15033937
|
| 2004 |
A silent mutation (c.165C>T) in exon 1 of the human ALG3 gene activates a cryptic donor splice site, deleting c.160_196 and generating a premature termination codon after the first N-terminal transmembrane domain (p.Val54fsX66); the resulting truncated ALG3 mRNA escapes nonsense-mediated mRNA decay (NMD) despite fulfilling NMD criteria, as demonstrated by cycloheximide treatment having no effect on transcript levels. |
RT-PCR analysis of patient transcripts; cycloheximide treatment to suppress NMD; expression studies in patient cells |
Human mutation |
Medium |
15108280
|
| 2021 |
ALG3 promotes radioresistance and cancer stemness in breast cancer cells by inducing glycosylation of TGF-β receptor II (TGFBR2); both pharmacological inhibition of glycosylation (tunicamycin) and TGFBR2 inhibition (LY2109761) abrogated the stimulatory effects of ALG3 overexpression on stemness and radioresistance, establishing TGFBR2 glycosylation as the mechanistic link. |
Immunoprecipitation; Western blot; shRNA knockdown; overexpression in breast cancer cell lines; orthotopic xenograft models; pharmacological inhibitor experiments |
Journal of experimental & clinical cancer research : CR |
Medium |
33931075
|
| 2022 |
ALG3 promotes ovarian cancer peritoneal metastasis by catalyzing alpha-1,3-mannosylation of urokinase plasminogen activator receptor (uPAR), which enhances uPA/uPAR activation and the interaction between uPAR and ADAM8, thereby activating the ADAM8/Ras/ERK signaling pathway. |
Lectin chip; Western blot; Lectin blot; Co-immunoprecipitation of uPAR and ADAM8; ALG3 knockdown in ovarian cancer cells; mouse peritoneal metastasis model |
Cells |
Medium |
36231102
|
| 2022 |
ALG3 inhibition induces deficiency of post-translational N-linked glycosylation, leading to excessive lipid accumulation through SREBP1-dependent lipogenesis in cancer cells; N-linked glycosylation deficiency-mediated lipid hyperperoxidation triggers immunogenic ferroptosis and promotes a pro-inflammatory tumor microenvironment that boosts anti-tumor immune responses and synergizes with anti-PD1 therapy. |
CRISPR/Cas9 ALG3 deletion in mouse cancer cells; lipid accumulation assays; SREBP1 pathway analysis; in vivo syngeneic tumor models with anti-PD1 combination; tunicamycin treatment as pharmacological comparator |
Cellular and molecular life sciences : CMLS |
Medium |
35676564
|
| 2025 |
AKT directly phosphorylates ALG3 at Ser11/Ser13 in the amino-terminal region downstream of the PI3K/AKT pathway in growth factor-stimulated and PI3K/AKT-hyperactive cancer cells; CRISPR/Cas9 depletion of ALG3 causes improper glycan formation, ER stress, unfolded protein response induction, and impaired cell proliferation; phosphorylation at Ser11/Ser13 is required for proper glycosylation of cell surface receptors EGFR, HER3, and E-cadherin. |
In vitro AKT kinase assay with ALG3 substrate; phosphorylation site identification (Ser11/Ser13); CRISPR/Cas9 ALG3 depletion; phospho-site mutagenesis; glycosylation analysis of EGFR, HER3, E-cadherin by Western blot; UPR marker analysis |
The Journal of biological chemistry |
High |
40236010 40789468
|
| 2025 |
ALG3 directly interacts with transcription factor FOXD1 and induces N-glycosylation at Asn176 of FOXD1, which increases FOXD1 protein stability and nuclear localization; this in turn allows FOXD1 to transcriptionally activate BNIP3, promoting mitophagy and gemcitabine resistance in nasopharyngeal carcinoma cells. |
Co-immunoprecipitation of ALG3 and FOXD1; glycosylation site mutagenesis (Asn176); nuclear fractionation; Western blot; BNIP3 transcriptional reporter/ChIP; cell proliferation and drug sensitivity assays |
International journal of biological sciences |
Medium |
40083705
|
| 2026 |
Cryo-EM structures of pseudo-Michaelis complexes of ALG3, ALG9, and ALG12 at high resolution revealed how the branched glycan is accurately synthesized in four consecutive mannosylation reactions converting GlcNAc2Man5 to GlcNAc2Man9; molecular dynamics simulations and mutagenesis uncovered the mechanism by which ALG3 selects the dolichylphosphomannose donor over dolichylphosphoglucose; the structures also provide mechanistic explanations for enzyme dysfunction in CDGs. |
Cryo-electron microscopy of pseudo-Michaelis complexes; chemoenzymatic synthesis of lipid-linked glycan analogs for in vitro reconstitution; molecular dynamics simulations; site-directed mutagenesis |
Nature chemical biology |
High |
41807832
|
| 2018 |
The human ALG3 protein (hNOT-1/ALG3-1) forms homodimers and interacts in vivo with OSBP, OSBPL9, LRP1, SYPL1, and the transcription factor CREB3 precursor (but not with CREB3 proteolytic products); binding to CREB3 precursor is a prerequisite for CREB3's proteolytic activation; different post-translationally processed ALG3 products localize to distinct cellular compartments and interact with different partners. |
Yeast two-hybrid screening; co-immunoprecipitation validation of selected interactions (OSBP, OSBPL9, LRP1, CREB3) in vivo |
Human molecular genetics |
Low |
29547901
|
| 2018 |
The human ALG3 (hNOT-1/ALG3-1) protein undergoes N-glycosylation and sequential proteolytic cleavage generating derivatives destined to distinct cellular compartments; truncated transcripts are not translated; two full-length precursor proteins (hNOT-1 and hNOT-4) are encoded by alternatively spliced transcripts differing at exon 1. |
Polyclonal antibodies against diverse protein regions; subcellular fractionation; Western blot analysis of N-glycosylation; RT-PCR and translation analysis of truncated transcripts |
Human molecular genetics |
Low |
30192950
|
| 2024 |
ALG3 deficiency in patient-derived fibroblasts results in constitutive activation of the unfolded protein response via the IRE1-α pathway, increased ER-associated degradation activity, and accumulation of N-linked Man3-4 glycans in cellular and secreted glycoproteins; in transferrin, the Man5 intermediate is further processed to a mono-antennary glycan NeuAc1Gal1GlcNAc1Man3GlcNAc2. |
Western blot of UPR markers in patient-derived fibroblasts; glycoprotein glycan profiling by mass spectrometry; IRE1-α pathway activation analysis |
Journal of inherited metabolic disease |
Medium |
38597022
|