Protein kinase C and AKT/protein kinase B in CD4+ T-lymphocytes: new partners in TCR/CD28 signal integration.

Abstract T-cell biological responses appear to involve the complex interaction of T-cell surface receptors, intracellular signaling molecules and the cytoskeleton. Both the serine/threonine protein kinase families protein kinase C (PKC) and protein kinase B or RAC-PK (AKT/PKB) have been implicated in signal transmission leading to activation, differentiation as well as cellular survival of T-lymphocytes. The PKC gene family consists of nine diverse isotypes (PKCα, β, γ, δ, e, ξ, η, θ and ι), the AKT/PKB gene family includes three kinases (AKT1/PKBα, AKT2/PKBβ, AKT3/PKBγ). Here, we attempt to summarize the regulation as well as downstream signaling pathways of PKC and AKT/PKB isotypes, that may act additive in TCR/CD28 induced proliferation and survival of peripheral CD4+ T-lymphocytes.