Isolation and Characterzation of p160.2,
a Signal Transducing Protein Downstream of Jak3
ZHU Jin-Fang, JI Hong-Bing, TANG Wei, LIU Xin-Yuan and ZHENG
Zhong-Cheng*
( Shanghai Institute of Biochemistry, the Academy of Sciences, Shanghai
200031, China )
Abstract Nonreceptor tyrosine kinase
Jak3, which binds to intracellular domain of interleukin-2 receptor gamma
subunit(IL-2Rγ), plays an important role in IL-2 function. To find downstream
signal transducer of Jak3, the N-terminal region JH3―JH7 of Jak3 was used as a
baitg to screen a cDNA library by using the yeast two-hybrid system. One real
true clone was obtained out of 105 cotransformants. Sequencing
indicated that it encoded a p160.2 protein fragment which consisted of 399
amino acid residues. Further results showed that the p160.2 fragment merely
bound to the intact JH3―JH7 through its C-terminal. Northern blot revealed that
human p160.2 shared homology with monkey p160.2, but was different from mouse
p160.2; and p160.2 was widely expressed in various tissues.
Key Words Jak3; signal transduction;
yeast two-hybrid system; p160.2
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