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Regulation of mitochondrial glycerol 3‐phosphate acyltransferase by phosphorylation‐dephosphorylation mechanism in 3T3‐L1 cells
Author(s) -
Zhang Man,
Pandey Atul,
Haldar Dipak
Publication year - 2010
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.24.1_supplement.694.17
Subject(s) - dephosphorylation , kinase , phosphorylation , protein kinase c , microbiology and biotechnology , casein kinase 2 , mitochondrion , chemistry , biochemistry , protein kinase a , casein kinase 1 , biology , phosphatase , mitogen activated protein kinase kinase
The posttranslational regulation of mitochondrial glycerol 3‐phosphate acyltransferase (mtGPAT) by phosphorylation‐dephosphorylation was investigated. All of the kinase sites were identified on the cDNA of the enzyme. The effects of four kinases, protein kinase C (PKC), protein kinase A (PKA), tyrosine kinase (TK) and casein Kinase II (CKII) were investigated either by treatment of isolated mitochondria with a kinase, or by treating intact cells with an activator or inhibitor of the kinase. Out of these kinases, PKC gave the highest stimulation (approximately 50%) of the mtGPAT with mitochondria isolated from 3T3‐L1 cells. MtGPAT was identified by Western Blot, or when the mitochondria or whole cells were incubated with γ‐ 32 P‐ATP, by autoradiography. PMA (0.1 μM), a stimulant for PKC, gave approximately 50% stimulation whereas AG490, AG1478 or Genistein (approximately 35 μM each), inhibitors of TK, caused approximately 50% inhibition of the mtGPAT when 3T3‐L1 cells were treated with these agents. Substantial inhibition of mtGPAT was also observed when the cells were treated with H‐7 (10 μM) or Gö6976 (10 μM). The data are in keeping with the view that the regulation of mtGPAT occurs not only at the level of transcription (Guha et al. , Arch. Biochem. Biophys. 490 (2009) 85–95), but also by phosphorylation‐dephosphorylation mechanism. Supported by NIH grant GM‐57643.