VPS4B Antibody [C16M22] | Primary Antibodies

Application: Reactivity: Human, Mouse, Rat

Usage Information

Dilution
WB1:100-1:1000 IP1:100-1:200 IHC1:50-1:500 IF1:50-1:500

Application
WB, IP, IHC, IF, ELISA

Reactivity
Human, Mouse, Rat

Source
Mouse Monoclonal Antibody

Storage Buffer
PBS, pH 7.2+50% Glycerol+0.05% BSA+0.01% NaN3

Storage (from the date of receipt)
-20°C (avoid freeze-thaw cycles), 2 years

Predicted MW
49 kDa

Datasheet & SDS

Biological Description

Specificity
VPS4B Antibody [C16M22] detects endogenous levels of total VPS4B protein.

Clone
C16M22

Synonym(s)
VPS4B, Vacuolar protein sorting-associated protein 4B, EC:3.6.4.6, Protein SKD1, SKD1, VPS42, VPS4-2, SKD1B, MIG1

Background
VPS4B (vacuolar protein sorting 4 homolog B) is an ATPase of the AAA family and a class E vacuolar protein sorting factor that localizes to endosomal membranes and functions as a key effector of the ESCRT machinery in the late steps of the endosomal multivesicular body (MVB) pathway. The protein contains an N‑terminal MIT (microtubule-interacting and trafficking) domain that binds ESCRT‑III subunits, followed by a large AAA ATPase cassette with Walker A/B and sensor motifs that assemble into higher-order oligomers, and a C‑terminal helix that participates in oligomer stabilization and substrate engagement. VPS4B recognizes membrane-associated ESCRT‑III polymers on endosomes via the MIT domain and uses ATP binding and hydrolysis in the AAA core to drive disassembly of ESCRT‑III filaments and release their subunits into the cytosol, which resets the ESCRT system for repeated cycles of MVB sorting and tightly couples ESCRT‑III turnover to membrane fission events that generate intraluminal vesicles. This activity positions VPS4B, together with its paralog VPS4A, as an essential regulator of cargo down-regulation, since MVBs deliver intraluminal vesicles to lysosomes for degradation of membrane proteins, including activated growth factor receptors, lysosomal enzymes, and lipids, and VPS4B-dependent ESCRT‑III recycling sustains the flux of receptors and transporters through this degradative route. VPS4B also participates in topologically similar membrane fission processes at the plasma membrane and midbody, where ESCRT‑III and VPS4 complexes mediate the final abscission step of cytokinesis and the budding of enveloped viruses such as HIV‑1, placing VPS4B at the intersection of cell division control, virus release, and endolysosomal traffic. Structural and mechanistic analysis shows that human VPS4B adopts a ring-competent ATPase conformation in which nucleotide-dependent conformational changes support mechanical remodeling of ESCRT‑III assemblies, and that the flexible MIT domain positions the ATPase core near ESCRT‑III polymers to coordinate recognition and disassembly. In hypoxic solid tumors, VPS4B expression is downregulated by the ubiquitin–proteasome system, and reduced VPS4B activity associates with impaired endosomal sorting, accumulation of epidermal growth factor receptor (EGFR), and prolonged EGFR signaling with enhanced induction of FOS/JUN and AP‑1 transcriptional activity, which links VPS4B-dependent endosomal maturation to growth factor receptor signaling dynamics under tumor hypoxia.

Background

VPS4B (vacuolar protein sorting 4 homolog B) is an ATPase of the AAA family and a class E vacuolar protein sorting factor that localizes to endosomal membranes and functions as a key effector of the ESCRT machinery in the late steps of the endosomal multivesicular body (MVB) pathway. The protein contains an N‑terminal MIT (microtubule-interacting and trafficking) domain that binds ESCRT‑III subunits, followed by a large AAA ATPase cassette with Walker A/B and sensor motifs that assemble into higher-order oligomers, and a C‑terminal helix that participates in oligomer stabilization and substrate engagement. VPS4B recognizes membrane-associated ESCRT‑III polymers on endosomes via the MIT domain and uses ATP binding and hydrolysis in the AAA core to drive disassembly of ESCRT‑III filaments and release their subunits into the cytosol, which resets the ESCRT system for repeated cycles of MVB sorting and tightly couples ESCRT‑III turnover to membrane fission events that generate intraluminal vesicles. This activity positions VPS4B, together with its paralog VPS4A, as an essential regulator of cargo down-regulation, since MVBs deliver intraluminal vesicles to lysosomes for degradation of membrane proteins, including activated growth factor receptors, lysosomal enzymes, and lipids, and VPS4B-dependent ESCRT‑III recycling sustains the flux of receptors and transporters through this degradative route. VPS4B also participates in topologically similar membrane fission processes at the plasma membrane and midbody, where ESCRT‑III and VPS4 complexes mediate the final abscission step of cytokinesis and the budding of enveloped viruses such as HIV‑1, placing VPS4B at the intersection of cell division control, virus release, and endolysosomal traffic. Structural and mechanistic analysis shows that human VPS4B adopts a ring-competent ATPase conformation in which nucleotide-dependent conformational changes support mechanical remodeling of ESCRT‑III assemblies, and that the flexible MIT domain positions the ATPase core near ESCRT‑III polymers to coordinate recognition and disassembly. In hypoxic solid tumors, VPS4B expression is downregulated by the ubiquitin–proteasome system, and reduced VPS4B activity associates with impaired endosomal sorting, accumulation of epidermal growth factor receptor (EGFR), and prolonged EGFR signaling with enhanced induction of FOS/JUN and AP‑1 transcriptional activity, which links VPS4B-dependent endosomal maturation to growth factor receptor signaling dynamics under tumor hypoxia.

References
https://pubmed.ncbi.nlm.nih.gov/16193069/ https://pubmed.ncbi.nlm.nih.gov/22252323/

Reference Table for Selecting PVDF Membrane Pore Size Specifications

Protein Size (kDa)	PVDF Transfer Membrane Pore Size (μm)
< 10	0.22
10-20	0.22
20-30	0.45
30-45	0.45
45-70	0.45
80-100	0.45
100-140	0.45
> 140	0.45

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Protein Size (kDa)	Separating Gel Percentage
4-40	20%
12-45	15%
10-70	12.5%
15-100	10%
25-100	8%
60-210	5%