title: Comparative Analysis of Transmembrane Regulators of the Filamentous Growth Mitogen-Activated Protein Kinase Pathway Uncovers Functional and Regulatory Differences.
abstract: Filamentous growth is a microbial differentiation response that involves the concerted action of multiple signaling pathways. In budding yeast, one pathway that regulates filamentous growth is a Cdc42p-dependent mitogen-activated protein kinase (MAPK) pathway. Several transmembrane (TM) proteins regulate the filamentous growth pathway, including the signaling mucin Msb2p, the tetraspan osmosensor Sho1p, and an adaptor Opy2p. The TM proteins were compared to identify common and unique features. Msb2p, Sho1p, and Opy2p associated by coimmunoprecipitation analysis but showed predominantly different localization patterns. The different localization patterns of the proteins resulted in part from different rates of turnover from the plasma membrane (PM). In particular, Msb2p (and Opy2p) were turned over rapidly compared to Sho1p. Msb2p signaled from the PM, and its turnover was a rate-limiting step in MAPK signaling. Genetic analysis identified unique phenotypes of cells overexpressing the TM proteins. Therefore, each TM regulator of the filamentous growth pathway has its own regulatory pattern and specific function in regulating filamentous growth. This specialization may be important for fine-tuning and potentially diversifying the filamentation response.
authors.affiliation: Department of Biological Sciences at the University at Buffalo, Buffalo, New York, USA.
authors.forename: Hema
authors.initials: H
authors.lastname: Adhikari
authors.affiliation: Department of Biological Sciences at the University at Buffalo, Buffalo, New York, USA.
authors.forename: Lauren M
authors.initials: LM
authors.lastname: Caccamise
authors.affiliation: Department of Biological Sciences at the University at Buffalo, Buffalo, New York, USA.
authors.forename: Tanaya
authors.initials: T
authors.lastname: Pande
authors.affiliation: Department of Biological Sciences at the University at Buffalo, Buffalo, New York, USA pjcullen@buffalo.edu.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Cullen
mesh_terms: D002462:Cell Membrane / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D020935:MAP Kinase Signaling System; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D021381:Protein Transport; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; C076360:MSB2 protein, S cerevisiae; D008565:Membrane Proteins; C547524:Opy2 protein, S cerevisiae; C459787:SHO1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins