| 2010 |
VIPAR (VIPAS39) forms a functional complex with VPS33B that interacts with RAB11A. Knockdown of vipar in zebrafish caused biliary excretion and E-cadherin defects. In Vipar- and Vps33b-deficient mouse mIMDC-3 cells, membrane proteins were expressed abnormally, tight junctions were structurally and functionally defective, Ceacam5 was mis-sorted toward lysosomal degradation, and E-cadherin was transcriptionally downregulated, establishing that the VPS33B-VIPAR complex regulates apical-basolateral polarity in liver and kidney. |
Co-immunoprecipitation (VPS33B-VIPAR-RAB11A complex), zebrafish vipar knockdown with biliary/E-cadherin readouts, Vipar/Vps33b-deficient mouse cell lines with tight junction functional assays, immunofluorescence, and protein sorting assays |
Nature genetics |
High |
20190753
|
| 2008 |
The human SPE-39 orthologue (C14orf133/VIPAS39) interacts with VPS33 homologues and co-immunoprecipitates and co-sediments with other HOPS complex subunits. SPE-39 knockdown in human cells altered morphology of syntaxin 7-, syntaxin 8-, and syntaxin 13-positive endosomes and delayed mannose 6-phosphate receptor-mediated cathepsin D delivery and EGF receptor degradation, establishing VIPAS39 as a regulator of lysosomal delivery via the HOPS complex. C. elegans SPE-39 interacts in vitro with both VPS33A and VPS33B, and RNAi of VPS33B phenocopies spe-39 spermatogenesis defects. |
Co-immunoprecipitation, co-sedimentation, in vitro binding assay, siRNA knockdown with fluorescence microscopy and trafficking assays (cathepsin D delivery, EGFR degradation), C. elegans genetic epistasis (RNAi) |
Molecular biology of the cell |
High |
19109425
|
| 2012 |
VPS16B (VIPAS39) was identified as a VPS33B-binding protein by yeast two-hybrid and mass spectrometry, confirmed by co-immunoprecipitation. In platelets from an ARC patient with C14orf133/VPS16B mutations, α-granules were completely absent while δ-granules were present. GFP-VPS16B in Dami megakaryocytic cells co-localized with markers of the trans-Golgi network, late endosomes, and α-granules, establishing that VPS16B is essential for platelet α-granule biogenesis. |
Yeast two-hybrid, mass spectrometry, co-immunoprecipitation, electron microscopy of patient platelets, immunofluorescence microscopy of GFP-VPS16B in Dami cells |
Blood |
High |
23002115
|
| 2013 |
Disease-causing mutations in VIPAS39/SPE-39 and VPS33B were investigated by yeast two-hybrid, immunoprecipitation, and quantitative fluorescent microscopy. Although few mutations prevent VIPAS39-VPS33B interaction, some mutants fragment VIPAS39-positive endosomes, and all mutants alter the subcellular localization of VPS33B to VIPAS39-positive endosomes, suggesting ARC syndrome results from impaired VIPAS39/SPE-39 and VPS33B-dependent endosomal maturation or fusion. |
Yeast two-hybrid, co-immunoprecipitation, quantitative fluorescent microscopy of mutant proteins in cells |
Human molecular genetics |
Medium |
23918659
|
| 2019 |
VPS33B and VPS16B (VIPAS39) form a small, distinct complex in megakaryocytes with the same hydrodynamic radius as the recombinant VPS33B-VPS16B heterodimer purified from bacteria. The complex localizes to recycling endosomes. VPS33B deficiency (CRISPR/Cas9 KO) causes α-granule cargo (platelet factor 4, von Willebrand factor, P-selectin) degradation in lysosomes rather than correct trafficking, and VPS16B steady-state levels are significantly lower in VPS33B-KO cells, indicating VPS16B is destabilized without VPS33B. |
CRISPR/Cas9 knockout in imMKCL megakaryocytes, size-exclusion chromatography, recombinant protein purification, immunofluorescence co-localization, immunoblotting for cargo proteins |
Blood advances |
High |
31501156
|
| 2023 |
Human VPS33B-VPS16B forms a high molecular weight complex (~315 kDa) with a VPS33B:VPS16B stoichiometry of 2:3. Structural analysis by CD, SAXS, and negative-staining EM revealed a well-folded α-helical, two-lobed shape, with each lobe containing one VPS33B molecule oriented in opposite directions. Truncated VPS16B (amino acids 143–316) is sufficient for complex formation with VPS33B. ARC-causing VPS33B missense variant L30P disrupts complex formation, whereas S243F and H344D do not. The bidirectional orientation of VPS33B molecules suggests the complex can interact with separate SNARE bundles/SNAREpins. |
Size-exclusion chromatography-multiangle light scattering (SEC-MALS), circular dichroism, small-angle X-ray scattering (SAXS), negative-staining EM, quantitative immunoblotting, avidin tagging, truncation/mutagenesis analysis |
The Journal of biological chemistry |
High |
37062417
|
| 2012 |
Tyrosine phosphorylation of SPE-39 (VIPAS39) following EGF stimulation promotes its ubiquitination at the C-terminal region, reducing SPE-39 stability. Ubiquitination is regulated by phosphorylation of Tyr-11. Association of VPS33B with SPE-39 inhibits EGF-stimulated ubiquitination of SPE-39, stabilizing it. SPE-39 and VPS33B have an opposing functional relationship in downregulation of the EGF receptor in EGF-stimulated COS-7 cells. |
Ubiquitination and phosphorylation assays (immunoprecipitation/immunoblotting), site-directed mutagenesis (Tyr-11), co-immunoprecipitation, EGF receptor downregulation assay in COS-7 cells |
FEBS letters |
Medium |
22677173
|
| 2018 |
VPS33B and VIPAR (VIPAS39) are essential for epidermal lamellar body biogenesis and function. Mouse knockouts of Vps33b or Vipas39 develop ichthyosis with abnormal lamellar body morphology, disrupted localization of lamellar body cargo, increased corneocyte thickness, decreased cornified envelope thickness, and reduced lipid deposition in stratum corneum, establishing a role for the VPS33B-VIPAR complex in lysosome-related organelle biogenesis in skin. |
Mouse knockout (Vps33b and Vipas39), histology, immunofluorescence, electron microscopy of skin biopsies and primary cells |
Biochimica et biophysica acta. Molecular basis of disease |
Medium |
29409756
|
| 2022 |
Stable expression of VPS16B (VIPAS39) in platelets, megakaryocytes, and other primary cells is dependent on VPS33B expression. A novel homozygous nonsense VPS33B variant in ARC syndrome patients caused loss of expression of both VPS33B and VPS16B in platelets, indicating VPS16B protein stability requires its partner VPS33B. |
Patient platelet protein expression analysis by immunoblotting, electron microscopy, confirmatory genetic testing |
Journal of thrombosis and haemostasis : JTH |
Medium |
35325493
|
| 2025 |
VIPAS39 was identified by IP-MS as a pivotal regulator that sorts ACSL4 into late endosomes, facilitating its release as exosomes. In ferroptosis-resistant ovarian cancer cells, VIPAS39 mediates exosomal export of ACSL4, reducing intracellular ACSL4 protein levels and conferring resistance to ferroptosis. Targeting VIPAS39 overcomes ferroptosis resistance and suppresses tumor growth in CDX and PDX models. |
Immunoprecipitation-mass spectrometry (IP-MS), live-cell imaging with pH-sensitive CD63-pHuji reporter, protein binding assays, cell viability and lipid peroxidation assays, CDX and PDX xenograft models |
EBioMedicine |
Medium |
40088627
|
| 2003 |
C. elegans SPE-39 (ortholog of VIPAS39) encodes a novel hydrophilic protein required for intracellular membrane reorganization during spermatogenesis. In spe-39 mutants, membranous organelles (MOs) are absent and fibrous bodies are disorganized, replaced by small vesicles with internal membranes. SPE-39 protein is distributed throughout the cytoplasm and not specifically associated with FB-MOs. The gene has orthologs in Drosophila and humans but no yeast homolog, suggesting a metazoan-specific membrane biogenesis function. |
Genetic analysis (spe-39 mutants), electron microscopy of spermatocytes, immunofluorescence with SPE-39-specific antiserum, gene identification/sequencing |
Genetics |
Medium |
14504223
|