脂肪酰化的小窝蛋白-2是胰岛素受体酪氨酸激酶的底物,用于胰岛素受体底物-1介导的信号激活。
Fatty acylated caveolin-2 is a substrate of insulin receptor tyrosine kinase for insulin receptor substrate-1-directed signaling activation.
作者信息
Kwon Hayeong, Lee Jaewoong, Jeong Kyuho, Jang Donghwan, Pak Yunbae
机构信息
Department of Biochemistry, Division of Applied Life Science (BK21 Plus Program), PMBBRC, Gyeongsang National University, Jinju 660-701, Republic of Korea.
Department of Biochemistry, Division of Applied Life Science (BK21 Plus Program), PMBBRC, Gyeongsang National University, Jinju 660-701, Republic of Korea.
出版信息
Biochim Biophys Acta. 2015 May;1853(5):1022-34. doi: 10.1016/j.bbamcr.2015.02.002. Epub 2015 Feb 7.
Here, we demonstrate that insulin receptor (IR) tyrosine kinase catalyzes Tyr-19 and Tyr-27 phosphorylation of caveolin-2 (cav-2), leading to stimulation of signaling proteins downstream of IR, and that the catalysis is dependent on fatty acylation status of cav-2, promoting its interaction with IR. Cav-2 is myristoylated at Gly-2 and palmitoylated at Cys-109, Cys-122, and Cys-145. The fatty acylation deficient mutants are unable to localize in the plasma membrane and not phosphorylated by IR tyrosine kinase. IR interacts with the C-terminal domain of cav-2 containing the cysteines for palmitoylation. IR mutants, Y999F and K1057A, but not W1220S, fail interaction with cav-2. Insulin receptor substrate-1 (IRS-1) is recruited to interact with the IR-catalyzed phospho-tyrosine cav-2, which facilitates IRS-1 association with and activation by IR to initiate IRS-1-mediated downstream signaling. Cav-2 fatty acylation and tyrosine phosphorylation are necessary for the IRS-1-dependent PI3K-Akt and ERK activations responsible for glucose uptake and cell survival and proliferation. In conclusion, fatty acylated cav-2 is a new substrate of IR tyrosine kinase, and the fatty acylation and phosphorylation of cav-2 present novel mechanisms by which insulin signaling is activated.
在此,我们证明胰岛素受体(IR)酪氨酸激酶催化小窝蛋白-2(cav-2)的酪氨酸-19和酪氨酸-27磷酸化,从而刺激IR下游的信号蛋白,并且该催化作用依赖于cav-2的脂肪酰化状态,促进其与IR的相互作用。Cav-2在甘氨酸-2处进行肉豆蔻酰化,在半胱氨酸-109、半胱氨酸-122和半胱氨酸-145处进行棕榈酰化。脂肪酰化缺陷型突变体无法定位于质膜,也不能被IR酪氨酸激酶磷酸化。IR与cav-2含有用于棕榈酰化的半胱氨酸的C末端结构域相互作用。IR突变体Y999F和K1057A,但不是W1220S,无法与cav-2相互作用。胰岛素受体底物-1(IRS-1)被招募与IR催化的磷酸化酪氨酸cav-2相互作用,这促进了IRS-1与IR的结合并被IR激活,从而启动IRS-1介导的下游信号传导。Cav-2的脂肪酰化和酪氨酸磷酸化对于负责葡萄糖摄取以及细胞存活和增殖的IRS-1依赖性PI3K-Akt和ERK激活是必需的。总之,脂肪酰化的cav-2是IR酪氨酸激酶的新底物,cav-2的脂肪酰化和磷酸化呈现了激活胰岛素信号传导的新机制。