Hasegawa Shinya, Inoue Daiki, Yamasaki Masahiro, Li Chuan, Imai Masahiko, Takahashi Noriko, Fukui Tetsuya
Department of Health Chemistry, Hoshi University, Shinagawa, Tokyo, Japan.
Laboratory of Physiological Chemistry, Institute of Medicinal Chemistry, Hoshi University, Shinagawa, Tokyo, Japan.
FEBS Lett. 2016 Jun;590(11):1592-601. doi: 10.1002/1873-3468.12197. Epub 2016 May 17.
Acetoacetyl-CoA synthetase (AACS) is a ketone body-utilizing enzyme and is responsible for the synthesis of cholesterol and fatty acids. We have previously shown that AACS is cleaved by legumain, a lysosomal asparaginyl endopeptidase. In this study, we attempted to determine the cleavage site of AACS. Mutagenesis analysis of AACS revealed that Asn547 is the specific cleavage site of AACS in mouse livers. The cleaved form of AACS (1-547) lost the ability to convert acetoacetate to acetoacetyl-CoA. Moreover, hydrodynamics-based gene transduction showed that overexpression of AACS (1-547) increases the protein expression of caveolin-1, the principal component of the caveolae. These results suggest that cleavage of AACS by legumain is critical for the regulation of enzymatic activity and results in gain-of-function changes.
乙酰乙酰辅酶A合成酶（AACS）是一种利用酮体的酶，负责胆固醇和脂肪酸的合成。我们之前已经表明，AACS会被溶酶体天冬酰胺基内肽酶legumain切割。在本研究中，我们试图确定AACS的切割位点。对AACS的诱变分析表明，Asn547是小鼠肝脏中AACS的特异性切割位点。AACS（1-547）的切割形式失去了将乙酰乙酸转化为乙酰乙酰辅酶A的能力。此外，基于流体动力学的基因转导表明，AACS（1-547）的过表达会增加小窝的主要成分小窝蛋白-1的蛋白质表达。这些结果表明，legumain对AACS的切割对于酶活性的调节至关重要，并导致功能获得性变化。
