| 2010 |
DNAJB12 (JB12) is an ER-localized, single membrane-spanning Hsp40 with its J-domain facing the cytosol. It binds Hsc70 via co-immunoprecipitation, recruits Hsc70 to the ER membrane, and cooperates with cytosolic Hsc70 and the ubiquitin ligase RMA1 to target nascent CFTR and CFTRΔF508 for proteasomal degradation. Overexpression of JB12 accelerates degradation of misfolded membrane proteins (but not misfolded luminal proteins), and knockdown increases CFTR folding efficiency up to threefold. |
Protease protection assay, immunofluorescence, co-immunoprecipitation, siRNA knockdown, overexpression with pulse-chase degradation assays, proteasome inhibitor (lactacystin) treatment |
Molecular biology of the cell / Cell structure and function |
High |
21148293 21150129
|
| 2014 |
Overexpression of DNAJB12 (or DNAJB14) causes formation of elaborate membranous structures (DJANGOS) within the nucleus, connected to the nuclear envelope via a novel nuclear pore configuration. DJANGOS contain DNAJB12, DNAJB14, Hsc70, and ER lumen/membrane markers. Genetic studies showed the chaperone activity of the DNAJ/Hsc70 system is required for DJANGOS formation. These structures dissolve during cell division and reform synchronously in daughter nuclei. |
Overexpression, immunofluorescence, electron microscopy (cryo-EM), live-cell imaging, genetic chaperone-activity mutants |
PloS one |
Medium |
24732912
|
| 2017 |
During severe ER stress, DNAJB12 is selectively degraded by the proteasome via ERAD complexes containing HERP, Sel1L, and gp78. JB12 is required to maintain BOK (a pro-apoptotic BCL-2 family member) at low levels; BOK was detected in complexes with JB12 and gp78 by co-immunoprecipitation. Depletion of JB12 leads to BOK accumulation and activation of Caspases 3, 7, and 9, sensitizing cells to proteotoxic and chemotherapeutic agents. |
siRNA knockdown, shRNA, proteasome inhibitor treatment, co-immunoprecipitation, caspase activity assays, Western blot |
The Journal of biological chemistry |
Medium |
28536268
|
| 2021 |
DNAJB12 and cytosolic Hsp70 maintain N1303K-CFTR misfolding intermediates in a detergent-soluble state with a ~3-h half-life. ERAD-resistant pools of N1303K-CFTR concentrate in ER tubules that associate with autophagy initiation sites (WIPI1, FIP200, LC3). Depletion of JB12 prevents entry of N1303K-CFTR into ER-connected phagophore membranes and traffic to autolysosomes. VX-809 stabilization of intermediates promotes their association with autophagy initiation machinery. DNAJB12 operates in biosynthetically active ER microdomains to triage membrane protein intermediates for ERAD versus ER-associated autophagy (ERAA). |
siRNA knockdown, detergent solubility assay, immunofluorescence colocalization, half-life/pulse-chase, pharmacological stabilization with VX-809, live imaging |
Molecular biology of the cell |
High |
33534640
|
| 2021 |
In planthopper vectors of a plant reovirus (SRBSDV), the viral nonstructural protein P7-1 and Hsc70 both directly bind the J-domain of DNAJB12. DNAJB12 overexpression induces ER retention of P7-1, while Hsc70 overexpression promotes transport of P7-1 from the ER to the cytosol for tubule assembly. The DNAJB12-Hsc70 complex is recruited to P7-1 tubules in midgut epithelial cells, and ATPase activity of Hsc70 is required for proper P7-1 tubule assembly. Knockdown of DNAJB12 or Hsc70 strongly inhibits tubule assembly in vivo. |
Co-immunoprecipitation/pulldown (direct binding to J-domain), overexpression, siRNA/RNAi knockdown, Hsc70 ATPase inhibitors, immunofluorescence colocalization in infected cells |
Molecular plant pathology |
Medium |
34668642
|
| 2022 |
DNAJB12 and Hsp70 maintain P23H-rhodopsin (P23H-R) in a detergent-soluble, ERAD-resistant conformation. P23H-R, DNAJB12, and FIP200 colocalize in foci at the rim of WIPI1 omegasome rings. Loss of DNAJB12 function prevents association of P23H-R-containing ER tubules with omegasomes. GABARAP facilitates transfer of P23H-R from ER-connected phagophores to autolysosomes that transiently dock with omegasomes; absence of GABARAP blocks this transfer without interfering with lysosome docking. |
DNAJB12 loss-of-function (KD/KO), immunofluorescence colocalization, live imaging, GABARAP genetic manipulation, detergent solubility assays |
Molecular biology of the cell |
High |
35704470
|
| 2023 |
DNAJB12 and DNAJB14 are structurally similar but non-redundant ER transmembrane Hsp40 co-chaperones. Their DUF1977 ER-lumen domains are dissimilar despite high J-domain homology. Both proteins undergo proteasomal degradation upon acute reductive challenge; DNAJB12 degradation is impaired by sulfenic-acid trapping with dimedone, implicating thiol oxidation in its regulation. Knockdown of DNAJB12 (and DNAJB14 or SGTA) impairs ER-to-cytosol translocation of PDI (ER protein reflux); DNAJB12 (but not DNAJB14) overexpression increases PDI cytosolic relocalization in non-stressed cells. |
siRNA knockdown, proteasome inhibitor treatment, dimedone thiol-trapping, subcellular fractionation, Western blot, interactome analysis |
Biochimica et biophysica acta. General subjects |
Medium |
37925033
|
| 2023 |
DNAJB12 knockout cells exhibit altered kinetics of phosphorylated Drp1 in response to CCCP-induced mitochondrial stress, and cells depleted of JB12 or JB14 show increased mitochondrial count and branching, suggesting a novel role for DNAJB12 in mitochondrial dynamics under stress. |
CRISPR knockout, Western blot for phospho-Drp1, mitochondrial morphology imaging |
Molecular and cellular biochemistry |
Low |
37851175
|
| 2025 |
DNAJB12 was identified as a direct interactor of the nucleic acid polymer REP 2139 by pulldown. Knockdown of DNAJB12 impedes morphogenesis and secretion of HBV subviral particles (SVPs), HBV virions, and infectious HDV, recapitulating antiviral effects of REP 2139, identifying DNAJB12 as its putative primary target and establishing a functional role for DNAJB12 in HBV/HDV particle morphogenesis. |
REP 2139 pulldown/bait identification, siRNA knockdown, viral particle production and secretion assays |
iScience |
Medium |
41684842
|