text: The calponin homology domain of Vav1 associates with calmodulin and is prerequisite to T cell antigen receptor-induced calcium release in Jurkat T lymphocytes.
  Vav1 is a guanine nucleotide exchange factor that is expressed specifically in hematopoietic cells and plays important roles in T cell development and activation. Vav1 consists of multiple structural domains so as to facilitate both its guanine nucleotide exchange activity and scaffold function following T cell antigen receptor (TCR) engagement. Previous studies demonstrated that the calponin homology (CH) domain of Vav1 is required for TCR-stimulated calcium mobilization and thus downstream activation of nuclear factor of activated T cells. However, it remained obscure how Vav1 functions in regulating calcium flux. In an effort to explore molecules interacting with Vav1, we found that calmodulin bound to Vav1 in a calcium-dependent and TCR activation-independent manner. The binding site was mapped to the CH domain of Vav1. Reconstitution of vav1-null Jurkat T cells (J.Vav1) with CH-deleted Vav1 exhibited a severe deficiency in calcium release to the same extent as that of Jurkat cells treated with the calmodulin inhibitor or J.Vav1 cells. The defect persisted even when phospholipase-Cgamma1 was fully activated, indicating a prerequisite role of Vav1 CH domain in calcium signaling. The results suggest that Vav1 and calmodulin function cooperatively to potentiate TCR-induced calcium release. This study unveiled a mechanism by which the Vav1 CH domain is involved in calcium signaling and provides insight into our understanding of the role of Vav1 in T cell activation.
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entities.type: CHEMICAL GENE-Y GENE-Y GENE-Y GENE-N GENE-Y GENE-N GENE-Y GENE-Y GENE-N CHEMICAL GENE-N GENE-Y GENE-Y GENE-N GENE-N GENE-N GENE-Y GENE-Y GENE-N GENE-Y CHEMICAL GENE-Y GENE-Y GENE-Y GENE-N GENE-N GENE-Y GENE-Y GENE-Y GENE-N GENE-Y CHEMICAL GENE-Y GENE-N GENE-Y GENE-N CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL
entities.text: calcium Vav1 calmodulin Vav1 guanine nucleotide exchange factor phospholipase-Cgamma1 Vav1 CH domain Vav1 calmodulin TCR guanine nucleotide Vav1 CH domain Vav1 Vav1 T cell antigen receptor TCR calponin homology (CH) domain Vav1 TCR nuclear factor of activated T cells Vav1 calcium Vav1 calmodulin Vav1 TCR CH domain Vav1 vav1 Vav1 CH Vav1 calcium Vav1 calponin homology domain calmodulin T cell antigen receptor calcium guanine nucleotide calcium calcium calcium calcium