The BioGRID | PUBLICATION VIEW

	J. Cell. Sci. Oct (2007); 120:3613-24
Proteins involved in sterol synthesis interact with Ste20 and regulate cell polarity-
Tiedje C, Holland DG, Just U, Hofken T
Institute of Biochemistry, Christian Albrecht University Kiel, Olshausenstrasse 40, 24098 Kiel, Germany- thoefken@biochem-uni-kiel-de
Abstract: The Saccharomyces cerevisiae p21-activated kinase -PAK- Ste20 regulates various aspects of cell polarity during vegetative growth, mating and filamentous growth- To gain further insight into the mechanisms of Ste20 action, we screened for interactors of Ste20 using the split-ubiquitin system- Among the identified proteins were Erg4, Cbr1 and Ncp1, which are all involved in sterol biosynthesis- The interaction between Ste20 and Erg4, as well as between Ste20 and Cbr1, was confirmed by pull-down experiments- Deletion of either ERG4 or NCP1 resulted in various polarity defects, indicating a role for these proteins in bud site selection, apical bud growth, cell wall assembly, mating and invasive growth- Interestingly, Erg4 was required for the polarized localization of Ste20 during mating- Lack of CBR1 produced no detectable phenotype, whereas the deletion of CBR1 in the absence of NCP1 was lethal- Using a conditional lethal mutant we demonstrate that both proteins have overlapping functions in bud morphology-
[PUBMED: 17895367]