Alternative p38 MAPK pathways

Abstract

There are four members of the mammalian p38 mitogen-activated protein kinases (MAPKs) family (p38α, p38β, p38γ, and p38δ) which are about 60% identical in their amino acid sequence but differ in their expression patterns, substrate specificities, and sensitivities to chemical inhibitors such as SB203580. Much attention in recent years has been focused on studying the role of the p38α isoform, which is widely referred to as p38 in the literature. However, there are other p38 isoforms (p38β, p38γ, and p38δ) whose roles among the cellular functions and the implication in some of the pathological conditions have not been precisely defined so far. Here, we focus on the emergent roles of the alternative p38γ and p38δ MAPK pathways and their implication in different biological processes. It is now clear that these p38MAPKs show similarities to the classical p38MAPK, but with some differences that challenge the paradigm of the archetypical p38MAPK pathway.