Coordinate regulation of the biosynthesis of ATP-citrate lyase and malic enzyme during adipocyte differentiation. Studies on 3T3-L1 cells.
The biosynthesis and degradation of two lipogenic enzymes were studied during the differentiation of 3T3-L1 preadipocytes into adipocytes. The activity and mass of malic enzyme, rose by an order of magnitude during adipocyte development and the enzyme accounted for 0.3% of the cytosol protein in mature fat cells. Similarly, the activity and amount of ATP-citrate lyase increased approximately 7-fold during the adipose conversion. The relative rates of synthesis of the two enzymes were less than or equal to 0.02% in preadipocytes, but increased sharply as the cells began to differentiate. Maximal steady state rates of malic enzyme and ATP-citrate lyase synthesis in 3T3-L1 adipocytes were 13- and 8-fold higher, respectively, than the basal rates in preadipocytes. In contrast, the half-lives of malic enzyme (67 h) and ATP-citrate lyase (47 h) were not altered during adipocyte development. Thus, accelerated rates of enzyme synthesis account for the differentiation-dependent accumulation of the two lipogenic enzymes. Increased rates of malic enzyme, ATP-citrate lyase, and fatty acid synthetase biosynthesis are expressed in a highly coordinated manner during adipocyte differentiation and are associated with parallel elevations in the levels of translatable mRNAs for these enzymes.
D001275:ATP Citrate (pro-S)-Lyase / Q000096:biosynthesis* / Q000378:metabolism; D000273:Adipose Tissue / Q000201:enzymology / Q000502:physiology*; D000818:Animals; D002415:Cats; D002417:Cattle; D002454:Cell Differentiation; D002478:Cells, Cultured; D003470:Culture Media; D007700:Kinetics; D008291:Malate Dehydrogenase / Q000096:biosynthesis* / Q000378:metabolism; D051379:Mice; D011061:Poly A / Q000235:genetics; D011132:Polyribosomes / Q000378:metabolism; D014176:Protein Biosynthesis; D012313:RNA / Q000235:genetics; D012333:RNA, Messenger
D003470:Culture Media; D012333:RNA, Messenger; D011061:Poly A; D012313:RNA; D008291:Malate Dehydrogenase; D001275:ATP Citrate (pro-S)-Lyase