Homo sapiens dullard protein phosphatase shows a preference for the insulin-dependent phosphorylation site of lipin1.

ABSTRACT: Human lipin1 catalyzes the highly regulated conversion of phosphatidic acids to diacylglycerides. Lipin's cellular location, protein partners, and biological function are directed by phosphorylation-dephosphorylation events catalyzed by the phosphoserine phosphatase dullard. To define the determinants of dullard substrate recognition and catalysis, and hence, lipin regulation, steady-state kinetic analysis was performed on phosphoserine-bearing nonapeptides based on the phosphorylation sites of lipin. The results demonstrate that dullard shows specificity for the peptide corresponding to the insulin-dependent phosphorylation site (Ser106) of lipin with a k(cat)/K(m) of 2.9 × 10(4) M(-1) s(-1). These results are consistent with a coil-loop structure for the insulin-dependent phosphorylation site on human lipin1 and make unlikely the requirement for an adaptor protein to confer activity such as that proposed for the yeast homologue.

SUBMITTER: Wu R 

PROVIDER: S-EPMC3338355 | biostudies-literature | 2011 Apr

REPOSITORIES: biostudies-literature