title: Megadalton-node assembly by binding of Skb1 to the membrane anchor Slf1.
abstract: The plasma membrane contains both dynamic and static microdomains. Given the growing appreciation of cortical microdomains in cell biology, it is important to determine the organizational principles that underlie assembly of compartmentalized structures at the plasma membrane. The fission yeast plasma membrane is highly compartmentalized by distinct sets of cortical nodes, which control signaling for cell cycle progression and cytokinesis. The mitotic inhibitor Skb1 localizes to a set of cortical nodes that provide spatial control over signaling for entry into mitosis. However, it has been unclear whether these nodes contain other proteins and how they might be organized and tethered to the plasma membrane. Here we show that Skb1 forms nodes by interacting with the novel protein Slf1, which is a limiting factor for node formation in cells. Using quantitative fluorescence microscopy and in vitro assays, we demonstrate that Skb1-Slf1 nodes are megadalton structures that are anchored to the membrane by a lipid-binding region in the Slf1 C-terminus. We propose a mechanism for higher-order node formation by Skb1 and Slf1, with implications for macromolecular assemblies in diverse cell types.
authors.affiliation: Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, NH 03755.
authors.forename: Lin
authors.initials: L
authors.lastname: Deng
authors.affiliation: Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, NH 03755.
authors.forename: Ruth
authors.initials: R
authors.lastname: Kabeche
authors.affiliation: Department of Molecular Genetics, Ohio State University, Columbus, OH 43210.
authors.forename: Ning
authors.initials: N
authors.lastname: Wang
authors.affiliation: Department of Molecular Genetics, Ohio State University, Columbus, OH 43210 Department of Molecular and Cellular Biochemistry, Ohio State University, Columbus, OH 43210.
authors.forename: Jian-Qiu
authors.initials: JQ
authors.lastname: Wu
authors.affiliation: Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, NH 03755 james.b.moseley@dartmouth.edu.
authors.forename: James B
authors.initials: JB
authors.lastname: Moseley
mesh_terms: D002462:Cell Membrane / Q000378:metabolism; D002853:Chromatography, Liquid; D017124:Conserved Sequence; D021962:Membrane Microdomains / Q000378:metabolism; D008780:Methyltransferases / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology; D008856:Microscopy, Fluorescence; D008958:Models, Molecular; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology; D012568:Schizosaccharomyces / Q000737:chemistry / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology; D053719:Tandem Mass Spectrometry
chemical_list: D016601:RNA-Binding Proteins; C000598031:SLF1 protein, S pombe; D029702:Schizosaccharomyces pombe Proteins; C102750:Skb1 protein, S pombe; D008780:Methyltransferases