SLC2A4/GLUT4 向细胞膜转运
中文名称
通路描述
在脂肪细胞和肌细胞中，胰岛素信号导致携带 GLUT4(SLC2A4) 葡萄糖转运蛋白的内质网囊泡向细胞膜转运，使细胞能够从血液中摄取葡萄糖（参见 Zaid 等 2008, Leney 和 Tavare 2009, Bogan 和 Kandror 2010, Foley 等 2011, Hoffman 和 Elmendorf 2011, Kandror 和 Pilch 2011, Jaldin-Fincati 等 2017）。在肌细胞中，肌肉收缩本身也可引起 GLUT4 的转运。尽管导致 GLUT4 转运的完整途径尚未阐明，但已知几个步骤。胰岛素激活激酶 AKT1 和 AKT2。肌肉收缩激活激酶 AMPK-alpha2 和可能也激活 AKT。AKT2 和（以较小程度）AKT1 磷酸化 RAB GTP 酶激活因子 TBC1D1 和 TBC1D4，使其结合 14-3-3 蛋白并失去 GTP 酶激活活性。结果 RAB 蛋白（可能是 RAB8A、RAB10、RAB14 和可能 RAB13）积累 GTP。RAB:GTP 与囊泡转运之间的联系尚不清楚，但可能涉及肌蛋白的招募和激活。肌蛋白 1C、2A、2B、5A 和 5B 均已被证明在将 GLUT4 囊泡转运至细胞周边起重要作用。在结合到细胞膜后，囊泡通过 VAMP2 与 SNAP23 和 SYNTAXIN-4 在细胞膜上的相互作用与细胞膜融合。
英文描述
mRNA Capping The 5'-ends of all eukaryotic pre-mRNAs studied thus far are converted to cap structures. The cap is thought to influence splicing of the first intron, and is bound by 'cap-binding' proteins, CBP80 and CBP20, in the nucleus. The cap is important for translation initiation, and it also interacts with the poly(A)terminus, via proteins, resulting in circularization of the mRNA to facilitate multiple rounds of translation. The cap is also important for mRNA stability, protecting it from 5' to 3' nucleases, and is required for mRNA export to the cytoplasm.The capping reaction usually occurs very rapidly on nascent transcripts; after the synthesis of only a few nucleotides by RNA polymerase II. The capping reaction involves the conversion of the 5'-end of the nascent transcript from a triphosphate to a diphosphate by a RNA 5'-triphosphatase, followed by the addition of a guanosine monophosphate by the mRNA guanylyltransferase, to form a 5'-5'-triphosphate linkage. This cap is then methylated by 2'-O-methyltransferases.
所含基因
28 个基因