title: Phospholipase Cβ1 induces membrane tubulation and is involved in caveolae formation.
abstract: Lipid membrane curvature plays important roles in various physiological phenomena. Curvature-regulated dynamic membrane remodeling is achieved by the interaction between lipids and proteins. So far, several membrane sensing/sculpting proteins, such as Bin/amphiphysin/Rvs (BAR) proteins, are reported, but there remains the possibility of the existence of unidentified membrane-deforming proteins that have not been uncovered by sequence homology. To identify new lipid membrane deformation proteins, we applied liposome-based microscopic screening, using unbiased-darkfield microscopy. Using this method, we identified phospholipase Cβ1 (PLCβ1) as a new candidate. PLCβ1 is well characterized as an enzyme catalyzing the hydrolysis of phosphatidylinositol-4,5-bisphosphate (PIP2). In addition to lipase activity, our results indicate that PLCβ1 possessed the ability of membrane tubulation. Lipase domains and inositol phospholipids binding the pleckstrin homology (PH) domain of PLCβ1 were not involved, but the C-terminal sequence was responsible for this tubulation activity. Computational modeling revealed that the C terminus displays the structural homology to the BAR domains, which is well known as a membrane sensing/sculpting domain. Overexpression of PLCβ1 caused plasma membrane tubulation, whereas knockdown of the protein reduced the number of caveolae and induced the evagination of caveolin-rich membrane domains. Taken together, our results suggest a new function of PLCβ1: plasma membrane remodeling, and in particular, caveolae formation.
authors.affiliation: Lipid Biology Laboratory, RIKEN, Saitama 351-0198, Japan;
authors.forename: Takehiko
authors.initials: T
authors.lastname: Inaba
authors.affiliation: Lipid Biology Laboratory, RIKEN, Saitama 351-0198, Japan; Department of Biochemistry, Kyorin University School of Medicine, Mitaka, Tokyo 181-8611, Japan;
authors.forename: Takuma
authors.initials: T
authors.lastname: Kishimoto
authors.affiliation: Lipid Biology Laboratory, RIKEN, Saitama 351-0198, Japan;
authors.forename: Motohide
authors.initials: M
authors.lastname: Murate
authors.affiliation: Lipid Biology Laboratory, RIKEN, Saitama 351-0198, Japan; Research Group of Biomolecular-Assembly, Department of Life Science and Medical Bioscience, Graduate School of Advanced Science and Engineering, Waseda University, Shinjuku-ku, Tokyo 162-8480, Japan;
authors.forename: Takuya
authors.initials: T
authors.lastname: Tajima
authors.affiliation: Lipid Biology Laboratory, RIKEN, Saitama 351-0198, Japan;
authors.forename: Shota
authors.initials: S
authors.lastname: Sakai
authors.affiliation: Lipid Biology Laboratory, RIKEN, Saitama 351-0198, Japan;
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Abe
authors.affiliation: Lipid Biology Laboratory, RIKEN, Saitama 351-0198, Japan;
authors.forename: Asami
authors.initials: A
authors.lastname: Makino
authors.affiliation: Lipid Biology Laboratory, RIKEN, Saitama 351-0198, Japan;
authors.forename: Nario
authors.initials: N
authors.lastname: Tomishige
authors.affiliation: Lipid Biology Laboratory, RIKEN, Saitama 351-0198, Japan;
authors.forename: Reiko
authors.initials: R
authors.lastname: Ishitsuka
authors.affiliation: Research Group of Biomolecular-Assembly, Department of Life Science and Medical Bioscience, Graduate School of Advanced Science and Engineering, Waseda University, Shinjuku-ku, Tokyo 162-8480, Japan;
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Ikeda
authors.affiliation: Research Group of Biomolecular-Assembly, Department of Life Science and Medical Bioscience, Graduate School of Advanced Science and Engineering, Waseda University, Shinjuku-ku, Tokyo 162-8480, Japan;
authors.forename: Shinji
authors.initials: S
authors.lastname: Takeoka
authors.affiliation: Lipid Biology Laboratory, RIKEN, Saitama 351-0198, Japan; UMR 7213 CNRS, University of Strasbourg, 67401 Illkirch, France toshihide.kobayashi@unistra.fr.
authors.forename: Toshihide
authors.initials: T
authors.lastname: Kobayashi
mesh_terms: D000818:Animals; D021941:Caveolae / Q000502:physiology*; D008081:Liposomes; D051379:Mice; D008810:Mice, Inbred C57BL; D054799:Phospholipase C beta / Q000378:metabolism*; D041701:Swiss 3T3 Cells
chemical_list: D008081:Liposomes; D054799:Phospholipase C beta
keywords: BAR-like domain; caveolae; membrane tubulation; microscopy screening; phospholipase Cβ1