background:
CHMP1B belongs to the chromatin-modifying protein/charged multivesicular body protein (CHMP) family. These proteins are components of ESCRT-III (endosomal sorting complex required for transport III), a complex involved in degradation of surface receptor proteins and formation of endocytic multivesicular bodies (MVBs). Some CHMPs have both nuclear and cytoplasmic/vesicular distributions, and one such CHMP, CHMP1A (MIM 112810), is required for both MVB formation and regulation of cell cycle progression
Function:
Probable peripherally associated component of the endosomal sorting required for transport complex III (ESCRT-III) which is involved in multivesicular bodies (MVBs) formation and sorting of endosomal cargo proteins into MVBs. MVBs contain intraluminal vesicles (ILVs) that are generated by invagination and scission from the limiting membrane of the endosome and mostly are delivered to lysosomes enabling degradation of membrane proteins, such as stimulated growth factor receptors, lysosomal enzymes and lipids. The MVB pathway appears to require the sequential function of ESCRT-O, -I,-II and -III complexes. ESCRT-III proteins mostly dissociate from the invaginating membrane before the ILV is released. The ESCRT machinery also functions in topologically equivalent membrane fission events, such as the terminal stages of cytokinesis and the budding of enveloped viruses (HISLV1 and other lentiviruses). ESCRT-III proteins are believed to mediate the necessary vesicle extrusion and/or membrane fission activities, possibly in conjunction with the AAA ATPase VPS4. Involved in cytokinesis. Involved in recruiting VPS4A and/or VPS4B and SPAST to the midbody of dividing cells. Involved in HISLV1 p6- and p9-dependent virus release.
Subunit:
Probable peripherally associated component of the endosomal sorting required for transport complex III (ESCRT-III). ESCRT-III components are thought to multimerize to form a flat lattice on the perimeter membrane of the endosome. Several assembly forms of ESCRT-III may exist that interact and act sequentally. Interacts with CHMP1A. Interacts with VTA1; the interaction probably involves the open conformation of CHMP1B. Interacts with CHMP2A. Interacts with VPS4A; the interaction is direct. Interacts with VPS4B; the interaction is direct. Interacts with SPAST (via MIT domain); the interaction is direct. Interacts with IST1. Interacts with MITD1. Interacts with STAMBP.
Subcellular Location:
Cytoplasm, cytosol. Endosome. Late endosome membrane; Peripheral membrane protein (Probable). Note=Localizes to the midbody of dividing cells, colocalizing with CEP55 and CHMP5. Localized at the periphery of the Fleming body.
Tissue Specificity:
Widely expressed. Expressed in pancreas, kidney, skeletal muscle, liver, lung, placenta and brain.
Similarity:
Belongs to the SNF7 family.
Database links:
UniProtKB/Swiss-Prot: Q7LBR1.1
Important Note:
This product as supplied is intended for research use only, not for use in human, therapeutic or diagnostic applications.
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