The BCKDH kinase and phosphatase integrate BCAA and lipid metabolism via regulation of ATP-citrate lyase

ABSTRACT: Strong associations exist between branched chain amino acids (BCAA) and dysregulated glucose and lipid metabolism, but the underlying mechanisms are not well understood. Here we report that inhibition of the kinase (BDK) or overexpression of the phosphatase (PPM1K) that regulate branched-chain ketoacid dehydrogenase (BCKDH), the committed step of BCAA catabolism, lowers circulating BCAA, reduces hepatic steatosis and improves glucose tolerance in the absence of weight loss in Zucker fatty rats. Phosphoproteomics analysis identified ATP-citrate lyase (ACL) as an alternate substrate of BDK and PPM1K. Overexpression of BDK in liver of lean rats increased ACL phosphorylation and activated de novo lipogenesis. Moreover, BDK and PPM1K transcript levels were increased and repressed, respectively, in response to fructose feeding and expression of the ChREBP transcription factor. These studies identify BDK and PPM1K as a regulatory node that integrates BCAA, glucose, and lipid metabolism via reciprocal regulation of BCKDH and ACL. Modulation of this node relieves key disease phenotypes in a genetic model of severe obesity and metabolic dysfunction.

INSTRUMENT(S): Q Exactive

ORGANISM(S): Rattus Norvegicus (rat)

TISSUE(S): Liver

SUBMITTER: Paul Grimsrud  

LAB HEAD: Christopher B. Newgard

PROVIDER: PXD009122 | Pride | 2018-05-18

REPOSITORIES: Pride