SH3GLB1
Description
The SH3GLB1 (SH3 domain containing GRB2 like, endophilin B1) is a protein-coding gene located on chromosome 1.
Endophilin-B1 is a protein that in humans is encoded by the SH3GLB1 gene. Endophilin-B1 belongs to the Bin/Amphiphysin/Rvs167 (BAR) family of proteins and plays a critical role in mitochondrial fission and fusion, as well as in autophagy and apoptosis. Loss of functional endophilin-B1 is seen in many different forms of cancer. The link between carcinogenesis and dysregulation of cell death pathways suggests that endophilin-B1 serves a critical tumor suppressor role in the cell, although the underlying mechanisms are not known.
== Structure ==
In the presence of model biological membranes, endophilin-B1 dimers assemble into helical scaffolds around the membrane and drive its tubulation.
== Interactions == In addition to the membrane binding and remodeling properties endophilin-B1 shares with many other BAR proteins, endophilin-B1 interacts with the pro-apoptotic factor Bcl-2-associated X protein (Bax) and SH3GLB2. It has also been shown to interact with a wide variety of proteins through a canonical SH3 domain that enables PxxP motif-containing protein interactions, including Beclin-1, amphiphysin-1, amphiphysin-2, and huntingtin.
May be required for normal outer mitochondrial membrane dynamics (PubMed:15452144). Required for coatomer-mediated retrograde transport in certain cells (By similarity). May recruit other proteins to membranes with high curvature. May promote membrane fusion (PubMed:11604418). Involved in activation of caspase-dependent apoptosis by promoting BAX/BAK1 activation (PubMed:16227588). Isoform 1 acts proapoptotic in fibroblasts (By similarity). Involved in caspase-independent apoptosis during nutrition starvation and involved in the regulation of autophagy. Activates lipid kinase activity of PIK3C3 during autophagy probably by associating with the PI3K complex II (PI3KC3-C2) (PubMed:17891140). Associated with PI3KC3-C2 during autophagy may regulate the trafficking of ATG9A from the Golgi complex to the peripheral cytoplasm for the formation of autophagosomes by inducing Golgi membrane tubulation and fragmentation (PubMed:21068542). Involved in regulation of degradative endocytic trafficking and cytokinesis, probably in the context of PI3KC3-C2 (PubMed:20643123). Isoform 2 acts antiapoptotic in neuronal cells; involved in maintenance of mitochondrial morphology and promotes neuronal viability (By similarity). {ECO:0000250|UniProtKB:Q9JK48, ECO:0000269|PubMed:11604418, ECO:0000269|PubMed:15452144, ECO:0000269|PubMed:17891140, ECO:0000269|PubMed:20643123, ECO:0000269|PubMed:21068542}
SH3GLB1 is also known as Bif-1, CGI-61, PPP1R70, dJ612B15.2.
