title: Perilipins are associated with cholesteryl ester droplets in steroidogenic adrenal cortical and Leydig cells.
abstract: Steroidogenic cells store cholesteryl esters, precursors for steroid hormone synthesis, in intracellular lipid droplets. Cholesteryl ester hydrolysis is activated by protein kinase A and catalyzed by cholesteryl esterase. The esterase is similar, if not identical, to hormone-sensitive lipase in adipocytes where an analogous lipolytic mechanism occurs. Perilipins, proteins located exclusively at lipid droplet surfaces in adipocytes, are polyphosphorylated by protein kinase A in response to lipolytic stimuli, suggesting a role for these proteins in mediating lipid metabolism. The present study reveals that perilipins are associated with cholesteryl ester droplets in two steroidogenic cell lines: Y-1 adrenal cortical cells and MA-10 Leydig cells. The relative abundance of perilipin mRNAs and protein is much less in steroidogenic cells than in adipocytes. Like adipocytes, steroidogenic cells express perilipin A; additionally, the latter cells contain relatively abundant amounts of perilipin C, a protein that is not detectable in adipocytes by Western analysis. The data suggest a strong link between perilipins and lipid hydrolysis that is mediated by the hormone-sensitive lipase/cholesteryl esterase class of enzymes.
authors.affiliation: Laboratory of Cellular and Developmental Biology, NIDDK, National Institutes of Health, Bethesda, Maryland 20892, USA.
authors.forename: D A
authors.initials: DA
authors.lastname: Servetnick
authors.forename: D L
authors.initials: DL
authors.lastname: Brasaemle
authors.forename: J
authors.initials: J
authors.lastname: Gruia-Gray
authors.forename: A R
authors.initials: AR
authors.lastname: Kimmel
authors.forename: J
authors.initials: J
authors.lastname: Wolff
authors.forename: C
authors.initials: C
authors.lastname: Londos
mesh_terms: D016475:3T3 Cells; D000273:Adipose Tissue / Q000378:metabolism; D000302:Adrenal Cortex / Q000737:chemistry* / Q000166:cytology; D000818:Animals; D002352:Carrier Proteins; D002478:Cells, Cultured; D002788:Cholesterol Esters / Q000032:analysis*; D007985:Leydig Cells / Q000737:chemistry*; D050356:Lipid Metabolism; D008297:Male; D051379:Mice; D000070778:Perilipin-1; D010750:Phosphoproteins / Q000032:analysis*; D012333:RNA, Messenger / Q000032:analysis; D013256:Steroids / Q000096:biosynthesis*
chemical_list: D002352:Carrier Proteins; D002788:Cholesterol Esters; D000070778:Perilipin-1; D010750:Phosphoproteins; D012333:RNA, Messenger; D013256:Steroids