Daniel Kornitzer, PhD
Associate Professor of Molecular Microbiology
PhD, 1991 - Hebrew University, Israel
Morphogenesis and iron acquisition in pathogenic fungi
Pathogenic microbes have evolved a large array of adaptations that allow them to survive and proliferate in the human host environment. Candida albicans is the most common systemic fungal pathogen, increasingly prevalent among immunosuppressed patients. We focus on two distinct adaptations of this organism to the host environment: 1) The ability to switch between yeast and mold morphologies, enabling Candida albicans to spread, attach and penetrate host tissues. Based on our identification of a role for phosphorylation and ubiquitin-mediated degradation in the suppression of this morphogenetic switch, we are now focusing on regulators that inhibit the switch from yeast to mold. 2) The ability to extract iron from host hemoglobin. We have identified a network of specialized cell surface heme-binding proteins that extract heme from hemoglobin and transfer it across the cell wall into the cell (Figure 1). We anticipate that molecular understanding of the factors required for Candida albicans virulence will lead ultimately to new ways to combat fungal infection.
Kuznets G, Vigonsky E, Weissman Z, Lalli D, Gildor T, Kauffman S, Turano P, Becker J, Lewinson O, and Kornitzer D. 2014. A relay network of extracellular heme-binding proteins drives C. albicans iron acquisition from hemoglobin. PLOS Pathogens 10(10), e1004407.
Simon E, Gildor T, and Kornitzer D. 2013. Phosphorylation of the cyclin CaPcl5 modulates both cyclin stability and specific recognition of the substrate. J. Mol. Biol. 425, 3151-3165.
Ofir A, Hofmann K, Weindling E, Gildor T, Baker K, Rogers PD, and Kornitzer D. 2012. Role of a Candida albicans Nrm1/Whi5 homolog in cell cycle gene expression and DNA replication stress response. Mol. Microbiology 84, 778-794.
Sela N, Atir-Lande A, and Kornitzer, D. 2012. Neddylation and CAND1 independently stimulate SCF ubiquitin ligase activity in Candida albicans. Euk. Cell 11, 42-52.
Aviram S and Kornitzer D. 2010. The Hul5 ubiquitin ligase promotes proteasomal processivity. Mol. Cell. Biol. 30, 985-994.
Schematic model of the heme relay network that extracts heme from hemoglobin and delivers it to the endocytic pathway via the CFEM proteins Rbt5, Pga7 and Csa2.