Anti-phospho-SIN1 (Thr398) from rabbit, purified by affinity chromatography

Target of rapamycin complex 2 subunit MAPKAP1 (UniProt: Q9BPZ7; also known as TORC2 subunit MAPKAP1, Mitogen-activated protein kinase 2-associated protein 1, Stress-activated map kinase-interacting protein 1, SAPK-interacting protein 1, mSIN1) is encoded by the MAPKAP1 (also known as MIP1, SIN1) gene (Gene ID: 79109) in human. mSIN1 is a subunit of mTORC2 regulates cell growth and survival in response to hormonal signals. It is ubiquitously expressed, with highest levels in heart and skeletal muscle. Six isoforms of SIN1 have been described that are produced by alternative splicing. All isoforms with the exception of isoform 4 can be incorporated into the mTORC2 complex. mTORC2 is shown to be activated by growth factors, but in contrast to mTORC1, it is nutrient-insensitive. mTORC2 phosphorylates serine 473 in Akt1, which facilitates the phosphorylation of Threonine 308 by PDK1, thereby allowing full activation of Akt. Genetic knockout of SIN1 is reported to abolish serine 473 phosphorylation of Akt and disrupts the RICTOR-mTOR interaction. mTORC2 also regulates the phosphorylation of SGK1 at serine 422. Within mTORC2, MAPKAP1 is required for complex formation and mTORC2 kinase activity. MAPKAP1 inhibits MAP3K2 by preventing its dimerization and auto-phosphorylation.