国产精品视频一区二区三区四,亚洲av美洲av综合av,99国内精品久久久久久久,欧美电影一区二区三区电影

VAV1, also known as Vav guanine nucleotide exchange factor 1, is a member of the Vav family of proteins. It is a dual-function guanine nucleotide exchange factor （GEF） that plays a crucial role in the regulation of T and B cell receptor signaling, T cell activation, T helper cell differentiation, and cytokine production. VAV1 is primarily expressed in hematopoietic cells, including T cells, B cells, monocytes, natural killer （NK） cells, granulocytes, and dendritic cells.