Protein-tyrosine Kinase Pyk2 Mediates Endothelin-induced p38 MAPK Activation in Glomerular Mesangial Cells

Abstract

Endothelin-1 (ET-1), a member of a family of 21 amino acid peptides possessing vasoconstrictor properties, is known to stimulate mesangial cell proliferation. In this study, ET-1 (100 nM) induced a rapid activation of p21 ras activation and suggested the involvement of the cytoplasmic proline-rich tyrosine kinase Pyk2. We have observed that Pyk2 was expressed in HMC and was tyrosine-phosphorylated within 5 min of ET-1 treatment. ET-1-induced activation of Pyk2 was further confirmed using phospho-specific anti-Pyk2 antibodies. Surprisingly, Src kinase activity was required upstream of ET-1-induced autophosphorylation of Pyk2. To determine whether Pyk2 autophosphorylation mediated ET-1-dependent p21 ras activation, adenovirus-mediated transfer was employed to express a dominantnegative form of Pyk2 (CRNK). CRNK expression inhibited ET-1-induced endogenous Pyk2 autophosphorylation, but did not abolish ET-1-mediated increases in GTP-bound p21 ras levels. ET-1-induced activation of the p38 MAPK (but not ERK) pathway was inhibited in HMC and in rat glomerular mesangial cells expressing the dominant-negative form of Pyk2. These findings suggest that the engagement of Pyk2 is important for ET-1-mediated p38 MAPK activation and hence the biological effect of this peptide in mesangial cells.

CRNK gene transfer improves function and reverses the myosin heavy chain isoenzyme switch during post-myocardial infarction left ventricular remodeling

“…Our results confirm earlier studies (15,(17)(18)(19)(20) and indicate that CRNK indeed functions as a dominant-negative inhibitor of PYK2 in cardiomyocytes. CRNK prevented PYK2 autophosphorylation at Y 402 in response to both ET and H 2 O 2 treatment of NRVM.…”

“…A replication-deficient Adv encoding FLAG-tagged, human CRNK (Adv-CRNK) was kindly provided by Dr. Andrey Sorokin, Medical College of Wisconsin (18). An Adv expressing GFP (Adv-GFP) was used to control for nonspecific effects of Adv infection (23).…”

“…When ectopically expressed, CRNK can inhibit PYK2 (but not FAK) tyrosine autophosphorylation at Y 402 , presumably by displacing PYK2 from its cytoskeleton-binding sites (15). Thus CRNK, like its structurally homologous polypeptide FRNK, has been used as a tool to specifically inhibit PYK2-dependent signal transduction (17)(18)(19)(20).…”

Essential role of Pyk2 and Src kinase activation in neuropeptide-induced proliferation of small cell lung cancer cells

“…Pyk2 signaling has been implicated in the activation of the ERK, JNK and p38MAPK pathways Tokiwa et al, 1996;Blaukat et al, 1999;Sorokin et al, 2001). Direct association of Src kinases with Pyk2 is essential for engaging the ERK/MAPK cascade (Blaukat et al, 1999;McMullen et al, 2004).…”

Soluble Fractalkine Prevents Monocyte Chemoattractant Protein-1-Induced Monocyte Migration via Inhibition of Stress-Activated Protein Kinase 2/p38 and Matrix Metalloproteinase Activities

“…Several reports have shown that activation of Pyk2 was necessary for the activation of ERKs and/or SAPKs in different cell lines and in response to various stimuli (47)(48)(49)(50)(51)(52). Thus, it was of interest to determine whether the inhibition by s-FKN of MCP-1-induced p38/SAPK2 activity, which leads to the abrogation of MCP-1-induced chemotaxis of MonoMac6 cells, was associated with an inhibition of Pyk2 activity.…”