Regulation of type-1 protein phosphatase in a model of metabolic arrest

Christopher J. Ramnanan, Kenneth B. Storey
2009 BMB Reports  
Type-1 phosphatase (PP-1) was assessed in foot muscle (FM) and hepatopancreas (HP) of estivating (EST) Otala lactea. Snail PP-1 displayed several conserved traits, including sensitivity to inhibitors, substrate affinity, and reduction in size to a 39 kDa catalytic subunit (PP-1c). During EST, PP-1 activity in FM and HP crude extracts was reduced, though kinetics and protein levels of purified PP-1c isoforms were not altered. PP-1c protein levels increased and decreased in nuclear and
more » ... lear and glycogen-associated fractions, respectively, during EST. Gel filtration determined that a 257 kDa low Km PP-1α complex decreased during estivation whereas a 76 kDa high Km complex increased in EST. Western blotting confirmed that the 76 kDa protein consisted of PP-1α and nuclear inhibitor of PP-1 (NIPP-1). A suppression of PP-1 activity factors in the overall metabolic rate depression in estivating snails and the mechanism is mediated through altered cellular localization and interaction with binding partners. [BMB reports 2009; 42(12): 817-822]
doi:10.5483/bmbrep.2009.42.12.817 pmid:20044954 fatcat:mbkpqjmkwbdwllwdba2ilg4o24