Rasシグナル伝達系制御におけるGTPase活性促進因子の多様性

概要

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The proto-oncogene ras is an essential gene for the growth and the differentiation for various types of cells. Ras, ras gene product, is a GTP binding protein which controls the signal transduction by GTP hydrolysis. The ras gene is frequently activated by point mutations in various types of human cancers, which results in a decrease in the GTPase activity of its product. A GTPase-activating protein p120 (p120GAP) was identified as a factor which stimulates the GTPase of normal ras gene product p21 but not of the mutated. An NF1 gene was identified as a gene whose loss of function causes an onset of human disorder, neurofibromatosis type I. The NF1 gene encodes a protein which contains a region with a similarity to the catalytic domain of p120GAP. We recently purified a novel Ras GAP whose molecular weight and immunogenecity are different from those of p120GAP and NF1. We named the novel mammalian Ras GAP as Gap1^m. Isolation and sequencing of Gap1^m cDNA revealed that Gap1^m is indeed a novel Ras GAP. We also succeeded in isolation of another novel Ras GAP gene, GapIII/Gap1^<IP4BP>, which is closely related to Gap1^m. Recently, it is shown that GapIII/Gap1^<IP4BP> binds inositol-tetrakis phosphate compounds. The overview of these Ras GAP molecules is described.
公益社団法人日本薬学会の論文
1996-01-25