The emerging role of protein kinase Cθ in cytoskeletal signaling.

Cytoskeletal rearrangements often occur as the result of transduction of signals from the extracellular environment. Efficient awakening of this powerful machinery requires multiple activation and deactivation steps, which usually involve phosphorylation or dephosphorylation of different signaling units by kinases and phosphatases, respectively. In this review, we discuss the signaling characteristics of one of the nPKC isoforms, PKCθ, focusing on PKCθ-mediated signal transduction to cytoskeletal elements, which results in cellular rearrangements critical for cell type-specific responses to stimuli. PKCθ is the major PKC isoform present in hematopoietic and skeletal muscle cells. PKCθ plays roles in T cell signaling through the IS, survival responses in adult T cells, and T cell FasL-mediated apoptosis, all of which involve cytoskeletal rearrangements and relocation of this enzyme. PKCθ has been linked to the regulation of cell migration, lymphoid cell motility, and insulin signaling and resistance in skeletal muscle cells. Additional roles were suggested for PKCθ in mitosis and cell-cycle regulation. Comprehensive understanding of cytoskeletal regulation and the cellular "modus operandi" of PKCθ holds promise for improving current therapeutic applications aimed at autoimmune diseases.