Wang T, Danielson P D, Li B Y, Shah P C, Kim S D, Donahoe P K
Pediatric Surgical Research Laboratories, Massachusetts General Hospital, Boston, MA 02114, USA.
Science. 1996 Feb 23;271(5252):1120-2. doi: 10.1126/science.271.5252.1120.
The alpha subunit of p21(RAS) farnesyltransferase (FNTA), which is also shared by geranylgeranyltransferase, was isolated as a specific cytoplasmic interactor of the transforming growth factor-beta (TGF-beta) and activin type I receptors with the use of the yeast two-hybrid system. FNTA interacts specifically with ligand-free TGF-beta type l receptor but is phosphorylated and released upon ligand binding. Furthermore, the release is dependent on the kinase activity of the TGF-beta type II receptor. Thus, the growth inhibitory and differentiative pathways activated by TGF-beta and activin involve novel mechanisms of serine-threonine receptor phosphorylation-dependent release of cytoplasmic interactors and regulation of the activation of small G proteins, such as p21(RAS).
p21（RAS）法尼基转移酶（FNTA）的α亚基也为香叶基香叶基转移酶所共有，利用酵母双杂交系统，该亚基被分离为转化生长因子-β（TGF-β）和激活素I型受体的一种特异性胞质相互作用分子。FNTA与无配体的TGF-β I型受体特异性相互作用，但在配体结合后会发生磷酸化并被释放。此外，这种释放依赖于TGF-β II型受体的激酶活性。因此，由TGF-β和激活素激活的生长抑制和分化途径涉及丝氨酸-苏氨酸受体磷酸化依赖性释放胞质相互作用分子以及调节小G蛋白（如p21（RAS））激活的新机制。
