Phospho-PPIG (Ser376) Antibody #3804

PPIG belongs to a highly conserved class of cyclophilins that function as peptidyl-prolyl-isomerases (PPIases) to catalyze the conversion of cis-proline to trans-proline in a polypeptide chain (1-4). PPIG contains an amino-terminal cyclophilin domain followed by Nopp140 repeats that are involved in its function as a nuclear chaperone (5). The carboxy-terminal of PPIG contains a SR (arginine-serine dipeptide repeat) domain (3,4) that is involved in pre-mRNA splicing and processing (6). PPIG interacts with the carboxy-terminal domain of RNA polymerase II as well as several other SR family splicing factors. These interactions lead to changes in localization and conformation and suggest a regulatory role in transcription and pre-mRNA splicing in the elongating RNA polymerase complex (7,8). PPIG is found in the nuclear matrix and nuclear speckles and is involved in the regulation of gene expression. PPIG shows a predominantly diffuse cytoplasmic distribution at the onset of mitosis, and in late telophase the isomerase is recruited to the newly formed nuclei (9).
Phosphorylation of Ser376 on PPIG was identified as a consensus site fit for ACG kinase at Cell Signaling Technology (CST) using PhosphoScan^®, a CST's LC-MS/MS platform for phosphorylation site discovery (10).