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ARS Home » Northeast Area » Boston, Massachusetts » Jean Mayer Human Nutrition Research Center On Aging » Research » Publications at this Location » Publication #163384
Title: LIPASE-SELECTIVE FUNCTIONAL DOMAINS OF PERILIPIN A DIFFERENTIALLY REGULATE CONSTITUTIVE AND PROTEIN KINASE A-STIMULATED LIPOLYSIS

Author
item ZHANG, HUI - TUFTS-HNRCA
item SOUZA, SANDRA - TUFTS-HNRCA
item MULIRO, KIZITO - TUFTS-HNRCA
item KRAEMER, FREDRIC - STANFORD UNIVERSITY
item OBIN, MARTIN - TUFTS-HNRCA
item GREENBERG, ANDREW - TUFTS-HNRCA

Submitted to: Journal of Biological Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/2/2003
Publication Date: 12/19/2003
Citation: ZHANG, H.H., SOUZA, S.C., MULIRO, K.V., KRAEMER, F.B., OBIN, M.S., GREENBERG, A.S. LIPASE-SELECTIVE FUNCTIONAL DOMAINS OF PERILIPIN A DIFFERENTIALLY REGULATE CONSTITUTIVE AND PROTEIN KINASE A-STIMULATED LIPOLYSIS. JOURNAL OF BIOLOGICAL CHEMISTRY. 2003;51:51535-51542.

Interpretive Summary: Perilipin (Peri) A is a fat droplet-associated protein that act dually to suppress constitutive fat breakdown and to enhance hormone-stimulated fat breakdown by enzymes called hormone sensitive lipase (HSL) and non-HSL lipase. To identify regions of Peri A that mediate these actions, we generated adenoviruses expressing native, truncated, or mutated Peri A and used these adenoviruses in a cell system to examine fat breakdown. We identified two special regions that are specific for HSL and non-HSL lipase in inhibiting constitutive but enhancing hormone-stimulated fat breakdown. Within these two regions, we identified sites that are phosphorylated in response to hormone treatment and mediate hormone-stimulated lipolysis. These results suggest a model of Peri A function and provide insights into the molecular mechanisms by which perilipin regulate fat metabolsim.

Technical Abstract: Perilipin (Peri) A is a lipid droplet-associated phosphoprotein that acts dually as a suppressor of basal (constitutive) lipolysis and as an enhancer of cyclic AMP-dependent protein kinase (PKA)-stimulated lipolysis by both hormone sensitive lipase (HSL) and non-HSL lipase(s). To identify domains of Peri A that mediate these multiple actions, we introduced adenoviruses expressing truncated or mutated Peri A and HSL into NIH 3T3 fibroblasts lacking endogenous perilipins and HSL but overexpressing acyl-CoA synthetase 1 and fatty acid transporter 1. We identified two lipase-selective functional domains: 1) Peri A (1-300 aa), which inhibits basal lipolysis and promotes PKA-stimulated lipolysis by HSL, 2) Peri A (301-517 aa), which inhibits basal lipolysis by non-HSL lipase and promotes PKA-stimulated lipolysis by both HSL and non-HSL lipase. PKA site mutagenesis revealed that PKA-stimulated lipolysis by HSL requires phosphorylation of one or more sites within Peri 1-300 (S for serine, S81, S222, S276). PKA-stimulated lipolysis by non-HSL lipase additionally requires phosphorylation of one or more PKA sites within Peri 301-517 (S433, S492, S517). Peri 301-517 promoted PKA-stimulated lipolysis by HSL, yet did not block HSL-mediated basal lipolysis indicating that an additional region(s) within Peri 301-517 promotes hormone-stimulated lipolysis by HSL. These results suggest a model of Peri A function in which 1) lipase-specific 'barrier' domains block basal lipolysis by HSL and non-HSL lipase, 2) differential PKA site phosphorylation allows PKA-stimulated lipolysis by HSL and non-HSL lipase, respectively, and 3) additional domains within Peri A further facilitate PKA-stimulated lipolysis, again with lipase selectivity.