Mitogen-Activated Protein Kinase Phosphatases (MKPs) in Fungal Signaling: Conservation, Function, and Regulation.
Mitogen-activated protein kinases (MAPKs) are key mediators of signaling in fungi, participating in the response to diverse stresses and in developmental processes. Since the precise regulation of MAPKs is fundamental for cell physiology, fungi bear dual specificity phosphatases (DUSPs) that act as MAP kinase phosphatases (MKPs). Whereas fungal MKPs share characteristic domains of this phosphatase subfamily, they also have specific interaction motifs and particular activation mechanisms, which, for example, allow some yeast MKPs, such as  Saccharomyces cerevisiae  Sdp1, to couple oxidative stress with substrate recognition. Model yeasts show that MKPs play a key role in the modulation of MAPK signaling flow. Mutants affected in  S. cerevisiae  Msg5 or in  Schizosaccharomyces pombe  Pmp1 display MAPK hyperactivation and specific phenotypes. MKPs from virulent fungi, such as  Candida albicans  Cpp1,  Fusarium graminearum  Msg5, and  Pyricularia oryzae  Pmp1, are relevant for pathogenicity. Apart from transcriptional regulation, MKPs can be post-transcriptionally regulated by RNA-binding proteins such as Rnc1, which stabilizes the  S. pombe   PMP1  mRNA.  P. oryzae  Pmp1 activity and  S. cerevisiae  Msg5 stability are regulated by phosphorylation and ubiquitination, respectively. Therefore, fungi offer a platform to gain insight into the regulatory mechanisms that control MKPs.
González-Rubio G, Fernández-Acero T, Martín H, Molina M