Cross-linking of FcγRIIIA (CD16) receptor on natural killer (NK) cells induces receptor-associated tyrosine kinase activation and tyrosine phosphorylation of numerous intracellular proteins, including phospholipase C (PLC)-γ1, PLC-γ2 and the associated ζ chain. Here we report that Vav, a proto-oncogene, also became tyrosine phosphorylated upon stimulation of CD16 in interleukin 2-activated NK cells (LAK-NK) as well as in an NK cell line, NK3.3. In addition, we observed that in LAK-NK cells, Vav was associated with a 70 kDa protein that also became tyrosine phosphorylated upon CD16 cross-linking. The association of this 70 kDa protein with Vav was disrupted by ionic detergent treatment. Tyrosine phosphorylation of Vav was inhibited by herbimycin A, a specific tyrosine kinase inhibitor. In vitro kinase assays with Vav immunoprecipitates derived from NK3.3 cells or LAK-NK cells resulted in the appearance of a phosphorylated 58 kDa protein, suggesting the presence of a kinase within the Vav immunoprecipitates. Cross-linking of CD16 did not enhance this Vav-associated kinase activity. Phosphoamino acid analysis of the 58 kDa protein revealed that it was phosphorylated only on serine and threonine residues, indicating that an unidentified serine/threonine kinase is constitutively associated with Vav. These observations suggest that the downstream signalling events regulated by Vav and its associated proteins are complex involving both tyrosine kinases as well as the yet unidentified serine/threonine kinase in NK cells.
Skip Nav Destination
Article navigation
September 1996
-
Cover Image
Cover Image
- PDF Icon PDF LinkTable of Contents
Research Article|
September 01 1996
Vav in natural killer cells is tyrosine phosphorylated upon cross-linking of Fcγ RIIIA and is constitutively associated with a serine/threonine kinase
Xiulong XU;
Xiulong XU
*
1Departments of General Surgery and Immunology/Microbiology, Rush-Presbyterian-St. Luke's Medical Center, Chicago, IL 60612, U.S.A.
*To whom correspondence should be addressed.
Search for other works by this author on:
Anita S.-F. CHONG
Anita S.-F. CHONG
1Departments of General Surgery and Immunology/Microbiology, Rush-Presbyterian-St. Luke's Medical Center, Chicago, IL 60612, U.S.A.
Search for other works by this author on:
Publisher: Portland Press Ltd
Received:
March 29 1996
Accepted:
May 08 1996
Online ISSN: 1470-8728
Print ISSN: 0264-6021
The Biochemical Society, London © 1996
1996
Biochem J (1996) 318 (2): 527–532.
Article history
Received:
March 29 1996
Accepted:
May 08 1996
Citation
Xiulong XU, Anita S.-F. CHONG; Vav in natural killer cells is tyrosine phosphorylated upon cross-linking of Fcγ RIIIA and is constitutively associated with a serine/threonine kinase. Biochem J 1 September 1996; 318 (2): 527–532. doi: https://doi.org/10.1042/bj3180527
Download citation file:
Sign in
Don't already have an account? Register
Sign in to your personal account
You could not be signed in. Please check your email address / username and password and try again.
Captcha Validation Error. Please try again.