Functional studies on native and mutated forms of perilipins: A role in protein kinase a-mediated lipolysis of triacylglycerols in Chinese hamster ovary cells

John T. Tansey, Anne M. Huml, Rainbow Vogt, Kathryn E. Davis, Jennifer M. Jones, Kathryn A. Fraser, Dawn L. Brasaemle, Alan R. Kimmel, Constantine Londos

Research output: Contribution to journalArticle

168 Scopus citations

Abstract

Perilipin A coats the lipid storage droplets in adipocytes and is polyphosphorylated by protein kinase A (PKA); the fact that PKA activates lipolysis in adipocytes suggests a role for perilipins in this process. To assess whether perilipins participate directly in PKA-mediated lipolysis, we have expressed constructs coding for native and mutated forms of the two major splice variants of the perilipin gene, perilipins A and B, in Chinese hamster ovary fibroblasts. Perilipins localize to lipid droplet surfaces and displace the adipose differentiation-related protein that normally coats the droplets in these cells. Perilipin A inhibits triacylglycerol hydrolysis by 87% when PKA is quiescent, but activation of PKA and phosphorylation of perilipin A engenders a 7-fold lipolytic activation. Mutation of PKA sites within the N-terminal region of perilipin abrogates the PKA-mediated lipolytic response. In contrast, perilipin B exerts only minimal protection against lipolysis and is unresponsive to PKA activation. Since Chinese hamster ovary cells contain no PKA-activated lipase, we conclude that the expression of perilipin A alone is sufficient to confer PKA-mediated lipolysis in these cells. Moreover, the data indicate that the unique C-terminal portion of perilipin A is responsible for its protection against lipolysis and that phosphorylation at the N-terminal PKA sites attenuates this protective effect.

Original languageEnglish (US)
Pages (from-to)8401-8406
Number of pages6
JournalJournal of Biological Chemistry
Volume278
Issue number10
DOIs
StatePublished - Mar 7 2003
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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