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The S accharomyces cerevisiae BEM 1 homologue in N eurospora crassa promotes co‐ordinated cell behaviour resulting in cell fusion
Author(s) -
Schürg Timo,
Brandt Ulrike,
Adis Christian,
Fleißner André
Publication year - 2012
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2012.08197.x
Subject(s) - biology , cell polarity , fusion protein , microbiology and biotechnology , polarity (international relations) , cell , biochemistry , gene , recombinant dna
Summary Directed growth or movement is a common feature of microbial development and propagation. In polar growing filamentous fungi, directed growth requires the interaction of signal sensing machineries with factors controlling polarity and cell tip extension. In N eurospora crassa an unusual mode of cell–cell signalling mediates mutual attraction of germinating spores, which subsequently fuse. During directed growth of the two fusion partners, the cells co‐ordinately alternate between two physiological stages, probably associated with signal sending and receiving. Here, we show that the S accharomyces cerevisiae BEM 1 homologue in N . crassa is essential for the robust and efficient functioning of this MAP kinase‐based signalling system. BEM 1 localizes to growing hyphal tips suggesting a conserved function as a polarity component. In the absence of BEM 1, activation of MAK ‐2, a MAP kinase essential for germling fusion, is strongly reduced and delayed. Germling interactions become highly instable and successful fusion is greatly reduced. In addition, BEM 1 is actively recruited around the forming fusion pore, suggesting potential functions after cell–cell contact has been established. By genetically dissecting the contribution of BEM 1 to additional various polarization events, we also obtained first hints that BEM 1 might function in different protein complexes controlling polarity and growth direction.