Protein Kinase A Subunit Balance Regulates Lipid Metabolism in Caenorhabditis elegans and Mammalian Adipocytes.
Protein kinase A (PKA) is a cyclic AMP (cAMP)-dependent protein kinase composed of catalytic and regulatory subunits and involved in various physiological phenomena, including lipid metabolism. Here we demonstrated that the stoichiometric balance between catalytic and regulatory subunits is crucial for maintaining basal PKA activity and lipid homeostasis. To uncover the potential roles of each PKA subunit, Caenorhabditis elegans was used to investigate the effects of PKA subunit deficiency. In worms, suppression of PKA via RNAi resulted in severe phenotypes, including shortened life span, decreased egg laying, reduced locomotion, and altered lipid distribution. Similarly, in mammalian adipocytes, suppression of PKA regulatory subunits RIα and RIIβ via siRNAs potently stimulated PKA activity, leading to potentiated lipolysis without increasing cAMP levels. Nevertheless, insulin exerted anti-lipolytic effects and restored lipid droplet integrity by antagonizing PKA action. Together, these data implicate the importance of subunit stoichiometry as another regulatory mechanism of PKA activity and lipid metabolism.
['Lee|Jung Hyun|JH|', 'Han|Ji Seul|JS|', 'Kong|Jinuk|J|', 'Ji|Yul|Y|', 'Lv|Xuchao|X|', 'Lee|Junho|J|', 'Li|Peng|P|', 'Kim|Jae Bum|JB|']
D041721:3T3-L1 Cells D000818:Animals D017173:Caenorhabditis elegans D029742:Caenorhabditis elegans Proteins D054757:Cyclic AMP-Dependent Protein Kinase RIIbeta Subunit D054756:Cyclic AMP-Dependent Protein Kinase RIalpha Subunit D050356:Lipid Metabolism D051379:Mice
protein kinase A (PKA) lipolysis lipid droplet stoichiometry adipose triglyceride lipase (ATGL)