Function and structure of lipid storage droplet protein 1 studied in lipoprotein complexes.
Triglycerides (TG) stored in lipid droplets (LDs) are the main energy reserve in all animals. The mechanism by which animals mobilize TG is complex and not fully understood. Several proteins surrounding the LDs have been implicated in TG homeostasis such as mammalian perilipin A and insect lipid storage proteins (Lsd). Most of the knowledge on LD-associated proteins comes from studies using cells or LDs leaving biochemical properties of these proteins uncharacterized. Here we describe the purification of recombinant Lsd1 and its reconstitution with lipids to form lipoprotein complexes suitable for functional and structural studies. Lsd1 in the lipid bound state is a predominately alpha-helical protein. Using lipoprotein complexes containing triolein it is shown that PKA mediated phosphorylation of Lsd1 promoted a 1.7-fold activation of the main fat body lipase demonstrating the direct link between Lsd1 phosphorylation and activation of lipolysis. Serine 20 was identified as the Lsd1-phosphorylation site triggering this effect.
Arrese
Estela L
EL
Department of Biochemistry and Molecular Biology, Oklahoma State University, 246 Noble Research Center, Stillwater, OK 74078, USA. estela@biochem.okstate.edu
Rivera
Laticia
L
Hamada
Masakazu
M
Mirza
Saima
S
Hartson
Steve D
SD
Weintraub
Susan
S
Soulages
Jose L
JL
D000595:Amino Acid Sequence; D000818:Animals; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D029721:Drosophila Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D004331:Drosophila melanogaster / Q000201:enzymology; D005216:Fat Body / Q000201:enzymology; D008049:Lipase / Q000737:chemistry / Q000502:physiology; D008066:Lipolysis; D008074:Lipoproteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D018402:Manduca; D008969:Molecular Sequence Data; D010089:Oxidoreductases, N-Demethylating / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D010715:Phosphatidylglycerols / Q000737:chemistry / Q000502:physiology; D010766:Phosphorylation; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology; D013329:Structure-Activity Relationship
D029721:Drosophila Proteins; D008074:Lipoproteins; D010715:Phosphatidylglycerols; D011994:Recombinant Proteins; C002773:dimyristoylphosphatidylglycerol; C524804:Lsd-1 protein, Drosophila; D010089:Oxidoreductases, N-Demethylating; D017868:Cyclic AMP-Dependent Protein Kinases; D008049:Lipase