FIG. 4.

Association of Clnk with HPK-1 in Cos-1 cells. (A) The ability of Clnk to associate with HPK-1 was examined by transient transfection in Cos-1 cells. An activated version of Lck (tyrosine 505 to phenylalanine 505; F505 Lck) was cotransfected in these cells in order to maximize protein tyrosine phosphorylation. The positions of HPK-1, Clnk, and Lck are shown on the left. Exposures: first panel, 3 h; second panel, 6 h; third panel, 3 h; fourth panel, 3 h; and fifth panel, 3 h. (B) Cos-1 cells were transiently transfected with cDNAs encoding HPK-1 and a FLAG-tagged version of Clnk (FLAG-Clnk). The association between HPK-1 and Clnk was then examined through probing of anti-HPK-1 (αHPK-1) immunoprecipitates by anti-Clnk (αClnk) immunoblotting. The migrations of HPK-1, FLAG-Clnk, and heavy chain of Ig [Ig(H)] are indicated on the left. Exposures, 6 h. αP.tyr, antiphosphotyrosine antibody.