title: Piecing together the puzzle of perilipin proteins and skeletal muscle lipolysis.
abstract: The regulation of skeletal muscle lipolysis and fat oxidation is a complex process involving multiple proteins and enzymes. Emerging work indicates that skeletal muscle PLIN proteins likely play a role in the hydrolysis of triglycerides stored in lipid droplets and the passage of fatty acids to the mitochondria for oxidation. In adipocytes, PLIN1 regulates lipolysis by interacting with comparative gene identification-58 (CGI-58), an activator of adipose triglyceride lipase (ATGL). Upon lipolytic stimulation, PLIN1 is phosphorylated, releasing CGI-58 to activate ATGL and initiate triglyceride breakdown. The absence of PLIN1 in skeletal muscle leads us to believe that other PLIN family members undertake this role. The focus of this review is on the PLIN family proteins expressed in skeletal muscle: PLIN2, PLIN3, and PLIN5. To date, most studies involving these PLIN proteins have used nonmuscle tissues and cell cultures to determine their potential roles. Results from work in these models support a role for PLIN proteins in sequestering lipases during basal conditions and in potentially working together for lipase translocation and activity during lipolysis. In skeletal muscle, PLIN2 tends to mirror the lipid content and may play a role in lipid droplet growth and stability through lipase interactions on the lipid droplet surface, whereas the skeletal muscle roles of both PLIN3 and PLIN5 seem to be more complex because they are found not only on the lipid droplet, but also at the mitochondria. Clearly, further work is needed to fully understand the intricate mechanisms by which PLIN proteins contribute to skeletal muscle lipid metabolism.
authors.affiliation: a Center for Bone and Muscle Health, Department of Kinesiology, Faculty of Applied Health Sciences, Brock University, St. Catharines, ON, Canada.|b Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON N1G 2W1, Canada.
authors.forename: Rebecca E K
authors.initials: RE
authors.lastname: MacPherson
authors.affiliation: a Center for Bone and Muscle Health, Department of Kinesiology, Faculty of Applied Health Sciences, Brock University, St. Catharines, ON, Canada.
authors.forename: Sandra J
authors.initials: SJ
authors.lastname: Peters
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism*; D006801:Humans; D008066:Lipolysis / Q000235:genetics / Q000502:physiology*; D051379:Mice; D009124:Muscle Proteins / Q000235:genetics / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000378:metabolism*; D000070778:Perilipin-1; D010750:Phosphoproteins / Q000235:genetics* / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D009124:Muscle Proteins; C000602978:PLIN1 protein, human; D000070778:Perilipin-1; D010750:Phosphoproteins; C000602979:Plin1 protein, mouse
keywords: exercice physique; exercise; gouttelettes de lipides; lipid droplets; lipolyse; lipolysis; muscle squelettique; perilipin; périlipines; skeletal muscle