Sterol-Rich Membrane Domains Define Fission Yeast Cell Polarity

• Published in: Cell Vol. 165; no. 5; pp. 1182 - 1196
• Main Authors: Makushok, Tatyana, Alves, Paulo, Huisman, Stephen Michiel, Kijowski, Adam Rafal, Brunner, Damian
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 19.05.2016
• Subjects: Actins - metabolism; cdc42 GTP-Binding Protein - metabolism; Cell Membrane - chemistry; Cell Polarity; Cytoskeleton - metabolism; Membrane Microdomains; Microtubule-Associated Proteins - metabolism; Schizosaccharomyces - chemistry; Schizosaccharomyces - cytology; Schizosaccharomyces - growth & development; Schizosaccharomyces - metabolism; Schizosaccharomyces pombe; Schizosaccharomyces pombe Proteins - metabolism
• ISSN: 0092-8674; 1097-4172
• DOI: 10.1016/j.cell.2016.04.037

Cell polarization is crucial for the functioning of all organisms. The cytoskeleton is central to the process but its role in symmetry breaking is poorly understood. We study cell polarization when fission yeast cells exit starvation. We show that the basis of polarity generation is de novo sterol biosynthesis, cell surface delivery of sterols, and their recruitment to the cell poles. This involves four phases occurring independent of the polarity factor cdc42p. Initially, multiple, randomly distributed sterol-rich membrane (SRM) domains form at the plasma membrane, independent of the cytoskeleton and cell growth. These domains provide platforms on which the growth and polarity machinery assembles. SRM domains are then polarized by the microtubule-dependent polarity factor tea1p, which prepares for monopolar growth initiation and later switching to bipolar growth. SRM polarization requires F-actin but not the F-actin organizing polarity factors for3p and bud6p. We conclude that SRMs are key to cell polarization. [Display omitted] •De novo cell polarization in fission yeast occurs in four distinct phases•Sterol-rich membrane domains define prospective growth sites•The microtubule/tea1p polarity cue polarizes sterol-rich membrane domains•cdc42p is not involved in de novo cell polarization Sterol-rich membrane domains of the fission yeast plasma membrane define prospective growth sites. Prior to growth initiation, these randomly distributed membrane patches move to cell poles, recruiting growth machinery and other polarity factors.