
Overview:
PTPRF or LAR is a member of the protein tyrosine phosphatase family with an extracellular region, a single transmembrane region, and two tandem intracytoplasmic catalytic domains (1). PTPRF has been shown to function in the regulation of epithelial cell-cell contacts at adherents junctions as well as in the control of beta-catenin signaling. An increased expression level of this protein was found in the insulin-responsive tissue of obese, insulin-resistant individuals, and may contribute to the pathogenesis of insulin resistance (2).
Gene Aliases:
LAR
Genbank Number:
NM_002840
References:
1.Ahmad, F. et al: Functional association between the insulin receptor and the transmembrane protein-tyrosine phosphatase LAR in intact cells. J. Biol. Chem. 272: 448-457, 1997. 2. Tsujikawa, K. et al: Distinct functions of the two protein tyrosine phosphatase domains of LAR (leukocyte common antigen-related) on tyrosine dephosphorylation of insulin receptor. Molec. Endocr. 15: 271-280, 2001. J. 2003 Aug 15;22(16):4121-31.
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根据磷酸化的底物不同,可将蛋白激酶分为组蛋白蛋白激酶、酪蛋白蛋白激酶等,但由于蛋白激酶可磷酸化底物的多样化,这种分法很不确切,已经被根据底物磷酸化氨基酸的分类方法所取代,有些如酪蛋白蛋白激酶,只是由于习惯而一直被沿用下来。根据有无调节物将蛋白激酶分为信使依赖的蛋白激酶和非信使依赖的蛋白激酶,有些信使依赖的蛋白激酶的首字母缩略词已为人们所接受,如cAMP依赖的蛋白激酶PKA、钙和磷脂依赖的蛋白激酶PKC以及钙依赖钙调素不依赖的蛋白激酶CDPK等,它们彼此间存在结构和功能上的相关关系。
也有人认为:蛋白激酶在信号转导中主要作用有两个方面:其一是通过磷酸化调节蛋白质的活性,磷酸化和去磷酸化是绝大多数信号通路组分可逆激活的共同机制,有些蛋白质在磷酸化后具有活性,有些则在去磷酸化后具有活性;其二是通过蛋白质的逐级磷酸化,使信号逐级放大,引起细胞反应.
根据PTK是否存在于细胞膜受体可将其分成受体型和非受体型。向左转|向右转

