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AMPK Regulates Lipolysis by Phosphorylation of Desnutrin/ATGL at Serine406
Author(s) -
Abbott Marcia J,
Sul Hei Sook
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.787.11
Subject(s) - ampk , lipolysis , phosphorylation , activator (genetics) , chemistry , protein kinase a , in vivo , adipose triglyceride lipase , metformin , microbiology and biotechnology , kinase , in vitro , adipose tissue , biochemistry , endocrinology , biology , insulin , gene
Desnutrin has been identified as the major triacylglycerol (TAG) lipase. However, very little is known about its direct activators. Phosphorylation sites have been identified in desnutrin, serine 406 and 430. We aimed to establish the regulatory activity of these residues in vitro and in vivo and to ask if AMPK is the kinase that phosphorylates these sites. Our data show that AMPK phosphorylates desnutrin at S406 but not S430 in vitro . HEK 293 cells were transfected with desnutrin or alanine mutants to prevent phosphorylation at S406, S430, or both. Glycerol release was measured after AICAR treatment, a potent AMPK activator. AICAR resulted in an increase in glycerol release in desnutrin overexpressing cells. S406 mutation (S406A) resulted in a reduction in glycerol release with control and AICAR cells. These data indicate that S406 is specifically required for desnutrin activity. To determine the physiological relevance in adipocytes, differentiated 3T3ΔCAR adipocytes were infected with desnutrin or S406A. AICAR and Metformin increased FA release over control cells. S406A decreased FA release with AICAR and Metformin treatments. To determine the consequence of S406 in vivo , desnutrin and S406A were introduced by adenovirus. S406A resulted in a decreased in vitro lipase activity and increased TAG. This study provides evidence for direct regulation of desnutrin activity, in vitro and in vivo, at S406 via AMPK.