Mislocalization and inhibition of acetyl-CoA carboxylase 1 by a synthetic small molecule.
Chromeceptin is a synthetic small molecule that inhibits insulin-induced adipogenesis of 3T3-L1 cells and impairs the function of IGF2 (insulin-like growth factor 2). The molecular target of this benzochromene derivative is MFP-2 (multifunctional protein 2). The interaction between chromeceptin and MFP-2 activates STAT6 (signal transducer and activator of transcription 6), which subsequently induces IGF inhibitory genes. It was not previously known how the binding of chromeceptin with MFP-2 blocks adipogenesis and activates STAT6. The results of the present study show that the chromeceptin-MFP-2 complex binds to and inhibits ACC1 (acetyl-CoA carboxylase 1), an enzyme important for the de novo synthesis of malonyl-CoA and fatty acids. The formation of this ternary complex removes ACC1 from the cytosol and sequesters it in peroxisomes under the guidance of Pex5p (peroxisomal-targeting signal type 1 receptor). As a result, chromeceptin impairs fatty acid synthesis from acetate where ACC1 is a rate-limiting enzyme. Overexpression of malonyl-CoA decarboxylase or siRNA (small interfering RNA) knockdown of ACC1 results in STAT6 activation, suggesting a role for malonyl-CoA in STAT6 signalling. The molecular mechanism of chromeceptin may provide a new pharmacological approach to selective inhibition of ACC1 for biological studies and pharmaceutical development.
Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Kyoto 606-8501, Japan. dongju@icems.kyoto-u.ac.jp
Dongju
D
Jung
Lutfi
L
Abu-Elheiga
Rie
R
Ayuzawa
Ziwei
Z
Gu
Takashi
T
Shirakawa
Yukio
Y
Fujiki
Norio
N
Nakatsuji
Salih J
SJ
Wakil
Motonari
M
Uesugi
D000103:Acetyl-CoA Carboxylase / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D000818:Animals; D001578:Benzopyrans / Q000737:chemistry* / Q000494:pharmacology*; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology; D056945:Hep G2 Cells; D006801:Humans
D001578:Benzopyrans; D004791:Enzyme Inhibitors; C560188:chromeceptin; D000103:Acetyl-CoA Carboxylase