Interaction
between Jak3 and Nucleosome Assembly Protein 1
JI Hong-Bin, ZHAI Qi-Wei, ZHU Jin-Fang, SUN Lan-Ying, LIU
Xin-Yuan, ZHENG Zhong-Cheng
(Shanghai Institute of Biochemistry, the Chinese Academy of Sciences,
Shanghai 200031, China)
Abstract Tyrosine
kinase Jak3 plays a critical role in the interleukin 2（IL-2） signaling because it
not only participates the Jak-Stat pathway, but also interacts with
unidentified signal transducers and regulates expression of some oncogenes such
as c-fos and c-myc. Abundant evidence demonstrated that
phosphorylated tyrosine was necessary for the interaction between two proteins.
Therefore, in order to clarify the role of Jak3 in IL-2 signal transduction,
the tyrosine-phosphorylation-involved yeast two-hybrid system was constructed
and the N-terminal region JH3―JH7 of Jak3 was used as a bait to screen a
peripheral blood cDNA library. About 50 double-positive colonies were obtained.
Sequence analysis indicated that one of them was from nucleosome assembly
protein 1 gene (Nap1）, and encoded a protein of 392
amino acid residues. Two-hybrid system results demonstrated that interaction
between Jak3 and Nap1 depended on the level of tyrosine phosphorylation.
Furthermore, immunoprecipitation and Western blot experiments confirmed that
Jak3 really interacted with Nap1 in murine pro-B lymphocyte BAF/BO3β cells.
Key words Jak3； signal transduction； tyrosine-phosphorylation
involved two-hybrid system； Nap1
Recevied: July 12,
1999 Accepted: August 20, 1999
* Corresponding author: Tel, 86-21-64374430; Fax, 86-21-64746127; e-mail, [email protected]