title: Pil1 controls eisosome biogenesis.
abstract: The molecular composition of plasma membranes is constantly remodeled by endocytosis and exocytosis. Eisosomes are large cytoplasmic protein assemblies that localize to specialized domains on the yeast plasma membrane. They are of uniform size and immobile, and their disruption leads to large aberrant plasma membrane invaginations and endocytic defects. It is unknown how eisosomes are formed or inherited and what governs their size, distribution, and location. Here we show that eisosomes are formed de novo in the bud of dividing cells. They colonize newly formed membrane at a fixed density in a polarized wave proceeding from the bud neck to the bud tip and become anchored at the site of their formation. Pil1, one of the two main eisosome subunits, emerges as the central regulator of eisosome biogenesis that determines both size and location of eisosomes. Lowering Pil1 expression leads to normal-sized eisosomes at a reduced density, suggesting that eisosomes must be of a minimal size. Conversely, raising Pil1 expression leads to larger eisosomes at a fixed density, suggesting that under these conditions eisosome nucleation sites are limiting. Pil1 expression is regulated by the cell cycle, which synchronizes eisosome formation with plasma membrane growth. Our results establish a first framework of the molecular principles that define eisosome assembly and distribution.
authors.affiliation: Howard Hughes Medical Institute, and Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, CA 94158, USA.
authors.forename: Karen E
authors.initials: KE
authors.lastname: Moreira
authors.forename: Tobias C
authors.initials: TC
authors.lastname: Walther
authors.forename: Pablo S
authors.initials: PS
authors.lastname: Aguilar
authors.forename: Peter
authors.initials: P
authors.lastname: Walter
mesh_terms: D002352:Carrier Proteins / Q000235:genetics; D002453:Cell Cycle; D002462:Cell Membrane / Q000378:metabolism; D016764:Cell Polarity; D049452:Green Fluorescent Proteins / Q000378:metabolism; D008668:Metallothionein; D046912:Multiprotein Complexes / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*
chemical_list: C500769:CUP1-1 protein, S cerevisiae; D002352:Carrier Proteins; D046912:Multiprotein Complexes; C487327:PIL1 protein, S cerevisiae; D010750:Phosphoproteins; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D049452:Green Fluorescent Proteins; D008668:Metallothionein