PPP1R8

This gene, through alternative splicing, encodes three different isoforms. Two of the protein isoforms encoded by this gene are specific inhibitors of type 1 serine/threonine protein phosphatases and can bind but not cleave RNA. The third protein isoform lacks the phosphatase inhibitory function but is a single-strand endoribonuclease comparable to RNase E of E. coli. This isoform requires magnesium for its function and cleaves specific sites in A+U-rich regions of RNA. [provided by RefSeq]

Full Name

protein phosphatase 1, regulatory (inhibitor) subunit 8

Function

Inhibitor subunit of the major nuclear protein phosphatase-1 (PP-1). It has RNA-binding activity but does not cleave RNA and may target PP-1 to RNA-associated substrates. May also be involved in pre-mRNA splicing. Binds DNA and might act as a transcriptional repressor. Seems to be required for cell proliferation.
Isoform Gamma is a site-specific single-strand endoribonuclease that cleaves single strand RNA 3' to purines and pyrimidines in A+U-rich regions. It generates 5'-phosphate termini at the site of cleavage. This isoform does not inhibit PP-1. May be implicated in mRNA splicing.

Biological Process

Cell population proliferationIEA:Ensembl
mRNA processingIEA:UniProtKB-KW
Negative regulation of protein dephosphorylationManual Assertion Based On ExperimentIBA:GO_Central
RNA catabolic processManual Assertion Based On ExperimentTAS:ProtInc
RNA splicingIEA:UniProtKB-KW

Cellular Location

Nucleus
Nucleus speckle
Primarily, but not exclusively, nuclear.
Isoform Gamma
Cytoplasm
Found mainly in the cytoplasm.

PTM

May be inactivated by phosphorylation on Ser-199 or Ser-204 (By similarity).
Phosphorylated by Lyn in vitro on Tyr-264, and also on Tyr-335 in the presence of RNA.