| Title: | Ssk2 mitogen-activated protein kinase kinase kinase governs divergent patterns of the stress-activated Hog1 signaling pathway in Cryptococcus neoformans |
| Author(s): | Bahn YS; Geunes-Boyer S; Heitman J; |
| Address: | "Department of Bioinformatics and Life Science, Soongsil University, Seoul, Korea" |
| ISSN/ISBN: | 1535-9786 (Electronic) 1535-9778 (Print) 1535-9786 (Linking) |
| Abstract: | "The stress-activated p38/Hog1 mitogen-activated protein kinase (MAPK) pathway is structurally conserved in many diverse organisms, including fungi and mammals, and modulates myriad cellular functions. The Hog1 pathway is uniquely specialized to control differentiation and virulence factors in a majority of clinical Cryptococcus neoformans serotype A and D strains. Here, we identified and characterized the Ssk2 MAPKKK that functions upstream of the MAPKK Pbs2 and the MAPK Hog1 in C. neoformans. The SSK2 gene was identified as a potential component responsible for the difference in Hog1 phosphorylation between the serotype D f1 sibling strains B-3501 and B-3502 through comparative analysis of meiotic maps showing their meiotic segregation patterns of Hog1-dependent sensitivity to the antifungal drug fludioxonil. Ssk2 is the only component of the Hog1 MAPK cascade that is polymorphic between the two strains, and the B-3501 and B-3502 SSK2 alleles were distinguished by two coding sequence changes. Supporting this finding, SSK2 allele exchange completely interchanged the Hog1-controlled signaling patterns, related phenotypes, and virulence levels of strains B-3501 and JEC21. In the serotype A strain H99, disruption of the SSK2 gene enhanced capsule and melanin biosynthesis and mating efficiency, similar to pbs2 and hog1 mutations. Furthermore, ssk2Delta, pbs2Delta, and hog1Delta mutants were hypersensitive to a variety of stresses and resistant to fludioxonil. In agreement with these results, Hog1 phosphorylation was abolished in the ssk2Delta mutant, similar to what occurred in the pbs2Delta mutant. Taken together, these findings indicate that Ssk2 is a critical interface connecting the two-component system and the Pbs2-Hog1 MAPK pathway in C. neoformans" |
| Keywords: | "Animals Cryptococcus neoformans/genetics/*metabolism *Gene Expression Regulation, Fungal Genes, Fungal Genome, Fungal MAP Kinase Kinase Kinases Macrophages/metabolism/*microbiology Meiosis Mice Mitogen-Activated Protein Kinase Kinases/metabolism/*physiolo;" |
| Notes: | "MedlineBahn, Yong-Sun Geunes-Boyer, Scarlett Heitman, Joseph eng R21 AI070230/AI/NIAID NIH HHS/ R01 HL030923/HL/NHLBI NIH HHS/ R01AI39115/AI/NIAID NIH HHS/ R37 AI039115/AI/NIAID NIH HHS/ HL-30923/HL/NHLBI NIH HHS/ R21AI070230/AI/NIAID NIH HHS/ R01 AI039115/AI/NIAID NIH HHS/ Research Support, N.I.H., Extramural Research Support, Non-U.S. Gov't 2007/10/24 Eukaryot Cell. 2007 Dec; 6(12):2278-89. doi: 10.1128/EC.00349-07. Epub 2007 Oct 19" |
