4c0t
Candida albicans PKh Kinase Domain
Structural highlights
FunctionPKH2_CANAL Serine/threonine-protein kinase which is part sphingolipid-mediated signaling pathway that is required for the internalization step of endocytosis by regulating eisosome assembly and organization, and modulating the organization of the plasma membrane. Phosphorylates and activates PKC1. Activates YPK1 and YPK2, 2 components of signaling cascade required for maintenance of cell wall integrity. Required for stress-induced P-body assembly and regulates global mRNA decay at the deadenylation step.[UniProtKB:Q12236] Publication Abstract from PubMedThe phosphoinositide-dependent protein kinase 1, PDK1, is a master kinase that phosphorylates the activation loop of up to 23 AGC kinases. S. cerevisiae has three PDK1 orthologues, Pkh1-3, which also phosphorylate AGC kinases (e.g., Ypk, Tpk, Pkc1, and Sch9). Pkh1 and 2 are redundant proteins involved in multiple essential cellular functions, including endocytosis and cell wall integrity. Based on similarities with the budding yeast, the Pkh of fungal infectious species was postulated as a novel target for antifungals. Here, we found that depletion of Pkh eventually induces oxidative stress and DNA double-strand breaks, leading to programmed cell death. This finding supports Pkh as an antifungal target since pharmacological inhibition of Pkh would lead to the death of yeast cells, the ultimate goal of antifungals. It was therefore of interest to further investigate the possibility to develop Pkh inhibitors with selectivity for Candida Pkh that would not inhibit the human ortholog. Here, we describe C. albicans Pkh2 biochemically, structurally and by using chemical probes in comparison to human PDK1. We found that a regulatory site on the C. albicans Pkh2 catalytic domain, the PIF-pocket, diverges from human PDK1. Indeed, we identified and characterized PS77, a new small allosteric inhibitor directed to the PIF-pocket, which has increased selectivity for C. albicans Pkh2. Together, our results describe novel features of the biology of Pkh and chemical biology approaches that support the validation of Pkh as a drug target for selective antifungals. PIF-Pocket as a Target for C. albicans Pkh Selective Inhibitors.,Pastor-Flores D, Schulze JO, Bahi A, Giacometti R, Ferrer-Dalmau J, Passeron S, Engel M, Suss E, Casamayor A, Biondi RM ACS Chem Biol. 2013 Oct 18;8(10):2283-92. doi: 10.1021/cb400452z. Epub 2013 Aug, 22. PMID:23911092[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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