PDCD6IP
Description
The PDCD6IP (programmed cell death 6 interacting protein) is a protein-coding gene located on chromosome 3.
Programmed cell death 6-interacting protein also known as ALIX is a protein that in humans is encoded by the PDCD6IP gene. This gene encodes a protein thought to participate in programmed cell death. Studies using mouse cells have shown that overexpression of this protein can block apoptosis. In addition, the product of this gene binds to the product of the PDCD6 gene, a protein required for apoptosis, in a calcium-dependent manner. This gene product also binds to endophilins, proteins that regulate membrane shape during endocytosis. Overexpression of this gene product and endophilins results in cytoplasmic vacuolization which may be partly responsible for the protection against cell death.
== Function == PDCD6IP protein is part of ESCRT pathway. It participates in the membrane scission of the revers topology budding and participates in multivesicular body formation. It is also vital at the later stages and for successful completion of cytokinesis.
== Interactions == PDCD6IP has been shown to interact with PDCD6.
PDCD6IP is a multifunctional protein involved in various cellular processes, including endocytosis, multivesicular body (MVB) biogenesis, membrane repair, cytokinesis, apoptosis, and maintenance of tight junction integrity. It acts as a Class E VPS protein, participating in the concentration and sorting of cargo proteins within MVBs for incorporation into intralumenal vesicles (ILVs). This process involves the invagination and scission of the limiting membrane of the endosome. PDCD6IP binds to the phospholipid lysobisphosphatidic acid (LBPA), a molecule abundant in the internal membranes of MVBs. The MVB pathway relies on the sequential function of ESCRT-O, -I, -II, and -III complexes. The ESCRT machinery is also involved in topologically equivalent membrane fission events, such as the terminal stages of cytokinesis. PDCD6IP acts as an adapter for a subset of ESCRT-III proteins, such as CHMP4, enabling their function at distinct membranes. It is essential for the completion of cytokinesis. PDCD6IP may play a role in regulating both apoptosis and cell proliferation. It contributes to exosome biogenesis in collaboration with SDC1/4 and SDCBP. Through interactions with F-actin, PARD3, and TJP1, PDCD6IP ensures the proper assembly and positioning of the actomyosin-tight junction complex at the apical sides of adjacent epithelial cells. This complex defines a specific membrane domain crucial for maintaining epithelial cell polarity and barrier function.
PDCD6IP is also known as AIP1, ALIX, DRIP4, HP95, MCPH29.
