Functional expression of a MAP kinase kinase in COS cells and recognition by an anti‐STE7/byrl antibody

FEBS Letters

Haystead, Clare M.M.¹  Wu, Jie²  Gregory, Peter¹  Haystead, Timothy A.J.¹  Sturgill, Thomas W.² 

[1] Departments of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA;Departments of Internal Medicine University of Virginia, Charlottesville, VA 22908, USA

关键词: MAP;    mitogen-activated protein;    MAPK;    MAP kinase;    MAPKK;    MAP kinase kinase;    p42mapk;    42 kDa MAPK;    p44mapk;    44 kDa MAPK;    PP-2A;    protein phosphatase 2A;    PTPase;    protein tyrosine phosphatase;    KLH;    keyhole limpet hemocyanin;    MBP;    myelin basic protein;   

DOI  :  10.1016/0014-5793(93)81481-E

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Mitogen-activated protein (MAP) kinases 042^mapk and p44^mapk are activated by dual tyrosine and threonine phosphorylation in vivo. Both MAPKs are phosphorylated and activated in vitro by an activator recently identified as a protein-tyrosine/threonine kinase. We have isolated a putative cDNA for a MAP kinase kinase (MAPKK) and determined its structure [Proc. Natl. Acad. Sci. USA, in press]. The protein encoded by this cDNA shares sequence homology with two yeast protein kinases byrl and STE7. We now report that stimulation with serum of COS cells expressing this protein amplifies MAPK activator activity markedly. The increased activity co-migrates during chromatography with the expressed 45 kDa protein, recognized by an anti-STE7/byrl antibody, and is abrogated by treatment with phosphatase 2A. Thus, this cDNA encodes a functional MAPKK. The anti-STE7/byrl antibody also recognized a 46 kDa COS cell protein that was resolved from the expressed MAPKK by anion-exchange chromatography. This immunoreactive protein co-eluted with endogenous MAPKK activity, suggesting identification of the immunoreactive band as monkey MAPKK.

【 授权许可】

Unknown