Q13427

PPIG also known as CARS-Cyp, CASP10, PPIase G, Rotamase G, Cyclophilin G is a crucial member of the Moca family of cyclophilins, which are highly conserved and abundant cytosolic peptidyl-prolyl cis-trans isomerases. These proteins play a vital role in accelerating the isomerization of XaaPro peptide bonds, thereby facilitating proper protein folding, essential for maintaining cellular function and homeostasis. PPIG is predominantly localized in the nucleus and, during interphase, is found in nuclear speckles, where PPIG is involved in pre-mRNA splicing regulation. PPIG features an N-terminal cyclophilin-type domain, an acidic serine-rich region, and five Cdc2-type phosphorylation sites, along with serine-arginine repeats at the C-terminus. Notably, PPIG undergoes phosphorylation during mitosis by the Cdc2-cyclin B complex, indicating activity regulation throughout the cell cycle.