Cellular Localization of Components of Mitogen-activated Protein Kinase (MAPK) Cascades and Alternative Splicing

The mitogen-activated protein kinase ( MAPK) cascade is composed of mitogen-activated protein kinases ( MAPKs ),mitogen-activated protein kinase kinases ( MAPKKs ),mitogen-activated protein kinase kinase kinases ( MAPKKKs),which is highly conserved in eukaryotes. The intracellular signals were relayed and amplified through sequential phosphorylations of MAPKKK→MAPKK→MAPK. In plants,numerous studies show that MAPKs play an important role in the signaling of biotic and abiotic stresses,phytohormones,and cell cycle cues. The localization of the MAPK proteins involves dynamic changes after activated during various responses in plants. Alternative splicing is one of the important mechanisms used to regulate gene expression and is employed by all eukaryotes. Alternative splicing affects the binding property, intracellular localization, enzymatic activity, protein stability and posttranslational modification of a large number of proteins. Alternative splicing of MAPK genes generates different transcript variants that produce proteins with different subcellular localizations. In this review, we will discuss recent advances in relation to this aspect.