Regulation of Pyk2 expression by p56(Lck) in Jurkat T lymphocytes

Lysates from the Jurkat T lymphocyte cell line were immunoblotted with anti -Pyk2, and two major forms of Pyk2 were identified. When lysates from the p 56(Lek) negative (J.CaM1/Rep3) and CD45 negative Jurkat cell line derivativ es were immunoblotted with anti-Pyk2, only the lower mobility form of Pyk2 was predominant. Transfection of J.CaM1 cells with p56(Lek) restored expres sion of the multiple forms of Pyk2. Using RT-PCR, we found that both specie s of the alternatively spliced mRNA for Pyk2 were present in all of the lin es regardless of their ability to express CD45 or p56(Lek) protein. When p5 6(Lek) immunoprecipitates were immunoblotted with anti-Pyk2, only the highe r mobility form of Pyk2 immunoprecipitated with p56(Lek). These data demons trate that certain members of the Sre family of kinases interact preferenti ally with the different isoforms of Pyk2 and may have a role in the regulat ion of the Pyk2 protein in lymphocytes. (C) 2001 Elsevier Science Inc. All rights reserved.