WD repeat domain phosphoinositide-interacting protein 2 is a
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...
that in humans is encoded by the ''WIPI2''
gene
In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...
.
Function
WD40 repeat
The WD40 repeat (also known as the WD or beta-transducin repeat) is a short structural motif of approximately 40 amino acids, often terminating in a tryptophan-aspartic acid (W-D) dipeptide. Tandem copies of these repeats typically fold togeth ...
proteins are key components of many essential biologic functions. They regulate the assembly of multiprotein complexes by presenting a beta-propeller platform for simultaneous and reversible protein-protein interactions. Members of the WIPI subfamily of WD40 repeat proteins, such as WIPI2, have a 7-bladed propeller structure and contain a conserved motif for interaction with phospholipids.
WIPI2 is the mammalian homolog of Atg18, not Atg21, along with the closely related protein,
WIPI1. WIPI2 mRNA is readily detectable in several commonly used laboratory cell lines (HEK293A, HeLa, A431) and several cancer cell lines, while WIPI1 expression is limited to cancer cells (but is also detected in many human tissues).
The Atg proteins regulate
autophagy, which is a
lysosomal
A lysosome () is a membrane-bound organelle found in many animal cells. They are spherical vesicles that contain hydrolytic enzymes that can break down many kinds of biomolecules. A lysosome has a specific composition, of both its membrane pro ...
degradation pathway required for maintaining cell health, surviving periods of nutrient deprivation and also plays a role in cancer, neurodegeneration and immune responses to a diverse range of pathogens.
WIPI2 is recruited early to the forming autophagosome, along with DFCP-1, ULK-1 and Atg16, where it positively regulates the lipidation of Atg8 (LC3). This is not true for WIPI1.
See also
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WIPI protein family
The WIPI protein family (WD-repeat protein Interacting with PhosphoInositides) is an evolutionarily conserved family of proteins. WIPI proteins contain a WD repeat domain that folds into a 7-bladed beta-propeller
In structural biology, a beta-pro ...
References
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Further reading
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