Although the zeta-associated protein of 70 kDa (ZAP-70) is overexpressed in patients with chronic lymphocytic leukemia (CLL) displaying unmutated IGVH genes and poor prognosis, a previous microarray study from our group identified overexpression of LPL and ADAM29 genes among unmutated and mutated CLL, respectively. To assess the prognostic value of these genes, we quantified their expression by...

ZAP-70 is a critical protein tyrosine kinase in T-cell activation and proliferation processes. Defective recruitment of ZAP-70 molecules results in termination of the T-cell receptor (TCR) signal transduction pathway. Impairment of this pathway is one of the early markers of disease progression in HIV-1 infected individuals. T-cell dysfunction in HIV infected patients may be connected to a defe...

ZAP-70 in chronic lymphocytic leukemia (CLL) has been associated with enhanced Bcell receptor (BCR) signaling, survival and migration. We investigated whether ZAP-70 can directly govern migration and the underlying mechanisms. In the ZAP-70 stablytransfected Ramos cell line, IgM stimulation but no IgD enhanced phosphorylation of ERK1/2, Akt and Syk, and delayed IgM and CD79b internalization. In...

The ZAP-70 protein is a member of the Syk/ZAP protein tyrosine kinase family, normally expressed in T cells and NK cells but not found in normal, mature B cells. The protein plays a critical role in the initiation of T-cell signaling. Leukemic cells from patients with B-cell chronic lymphocytic leukemia (B-CLL) that expressed nonmutated immunoglobulin V genes were found to express levels of ZAP...

T cell activation by antigens binding to the T cell receptor (TCR) must be properly regulated to ensure normal T cell development and effective immune responses to pathogens and transformed cells while avoiding autoimmunity. The Src family kinase Lck and the Syk family kinase ZAP-70 (ζ chain-associated protein kinase of 70 kD) are sequentially activated in response to TCR engagement and serve a...

The presence or absence of somatic mutations in the expressed immunoglobulin heavy chain variable regions (IgVH) of chronic lymphocytic leukemia (CLL) cells provides prognostic information. Patients whose leukemic cells express unmutated IgVH regions (Ig-unmutated CLL) often have progressive disease, whereas patients whose leukemic cells express mutated IgVH regions (Ig-mutated CLL) more often ...

UNLABELLED Serum thymidine kinase (TK), zeta-associated protein of 70 kDa (ZAP-70) and CD38 levels have been shown to be correlated with survival in chronic lymphocytic leukaemia (CLL). AIM To investigate the possible correlations between TK, ZAP-70 and CD38 levels as prognostic markers in new diagnosed Rai stages of CLL patients. METHODS 120 CLL patients were enrolled. ELISA was used to me...

ZAP-70 is a cytoplasmic protein tyrosine kinase that plays a critical role in the events involved in initiating T-cell responses by the antigen receptor. Here we review the structure of ZAP-70, its regulation, its role in development and in disease. We also describe a model experimental system in which ZAP-70 function can be interrupted by a small chemical inhibitor.

Regulation of protein tyrosine kinases (PTKs) by tyrosine phosphorylation is well recognized; in fact, nearly all PTKs require phosphorylation of tyrosine residues in their "activation loop" for catalytic activity. In contrast, the phosphorylation of PTKs on serine and threonine residues has not been studied nearly as much. We report that the ZAP-70 PTK contains predominately phosphoserine in n...

Engagement of the T cell antigen receptor (TCR) results in activation of several tyrosine kinases leading to tyrosine phosphorylation of protein substrates and activation of multiple biochemical pathways. TCR-mediated activation of the src-family kinases, Lck and Fyn, results in tyrosine phosphorylation of the TCR zeta and CD3 chains. The site of phosphorylation in these chains is the tyrosine-...