Physiological and Non-Redundant Functions of PKC Isotypes in T Lymphocytes

Abstract

This review is about the physiological and non-redundant functions of the PKC gene products in hematopoietic cells, particularly T cells. In spite of the large amount of information on PKC functions in various cell types and tissues, the characterization of the isotype selective functions of the entire PKC family in lymphoid cell lineages is far from complete. Given the established important role of PKC as regulator of T cell fate and knowing that several other PKC isotypes are also expressed in T cells at a high level, we here summarize the physiological and non-redundant functions of PKC , , , , and isotypes in T cells (with emphasis on the ongoing mouse genetic studies). Their known and/or suspected cellular regulation, effector pathways as well as physiological functions are discussed. While PKC , , and appear to be dispensable during cellular activation of primary CD3 + T cells, PKC and PKC take critical parts in signaling pathways that are necessary for full antigen receptor mediated T cell activation and T lymphocyte immunity.

Protein kinase C signaling and cell cycle regulation

“…However, PKCβ isozymes do not have an essential role in T cell function since PKCβ - / - mice have no appreciable T cell-related defects. This contrasts with a critical role for PKCβ in B cell receptor signaling (Thuille et al, 2006) and in dendritic cell differentiation (Farren et al, 2010). Thus, any role of PKCβI/II association with cytoskeletal elements is likely to be redundant.…”

“…T lymphocytes express all members of the PKC family with the exception of PKCγ (Koretzky et al, 1989; Chen et al, 1994; Thuille et al, 2006). A role for PKC isozymes in cell cycle regulation in CD3 + T lymphocytes was suggested by the early recognition that phorbol esters, in conjunction with calcium ionophore, are potent mitogens for these cells (Altman et al, 1990).…”