Swiprosin-1 Expression Is Up-Regulated through Protein Kinase C-θ and NF-κB Pathway in T Cells

Swiprosin-1 exhibits the highest expression in CD8(+) T cells and immature B cells and has been proposed to play a role in lymphocyte biology through actin remodeling. However, regulation of swiprosin-1 gene expression is poorly understood. Here we report that swiprosin-1 is up-regulated in T cells by PKC pathway. Targeted inhibition of the specific protein kinase C (PKC) isotypes by siRNA revealed that PKC-θ is involved in the expression of swiprosin-1 in the human T cells. In contrast, down-regulation of swiprosin-1 by A23187 or ionomycin suggests that calcium-signaling plays a negative role. Interestingly, swiprosin-1 expression is only reduced by treatment with NF-κB inhibitors but not by NF-AT inhibitor, suggesting that the NF-κB pathway is critical for regulation of swiprosin-1 expression. Collectively, these results suggest that swiprosin-1 is a PKC-θ-inducible gene and that it may modulate the late phase of T cell activation after antigen challenge.