Nimmy, Mohan and AP, Sudheesh and Nimmy, Francis and Richard, Anderson and Rakesh S, Laishram (2015) Phosphorylation regulates the Star-PAP-PIPKIα interaction and directs specificity toward mRNA targets. Nucleic acids research, 43. pp. 7005-7020. ISSN 1362-4962

Text Phosphorylation regulates( Nucl.Acids Res).pdf Restricted to Registered users only Download (7Mb) | Request a copy

Abstract

Star-PAP is a nuclear non-canonical poly(A) polymerase (PAP) that shows specificity toward mRNA targets. Star-PAP activity is stimulated by lipid messenger phosphatidyl inositol 4,5 bisphoshate (PI4,5P2) and is regulated by the associated Type I phosphatidylinositol-4-phosphate 5-kinase that synthesizes PI4,5P2 as well as protein kinases. These associated kinases act as coactivators of Star-PAP that regulates its activity and specificity toward mRNAs, yet the mechanism of control of these interactions are not defined. We identified a phosphorylated residue (serine 6, S6) on Star-PAP in the zinc finger region, the domain required for PIPKIα interaction. We show that S6 is phosphorylated by CKIα within the nucleus which is required for Star-PAP nuclear retention and interaction with PIPKIα. Unlike the CKIα mediated phosphorylation at the catalytic domain, Star-PAP S6 phosphorylation is insensitive to oxidative stress suggesting a signal mediated regulation of CKIα activity. S6 phosphorylation together with coactivator PIPKIα controlled select subset of Star-PAP target messages by regulating Star-PAP-mRNA association. Our results establish a novel role for phosphorylation in determining Star-PAP target mRNA specificity and regulation of 3'-end processing.

Item Type:	Article
Subjects:	Cardiovascular Diseases And Diabetes Biology
Depositing User:	Central Library RGCB
Date Deposited:	23 Dec 2016 04:24
Last Modified:	27 Dec 2016 07:07
URI:	http://rgcb.sciencecentral.in/id/eprint/54

Actions (login required)

View Item