title: Identification and characterization of Rvs162/Rvs167-3, a novel N-BAR heterodimer in the human fungal pathogen Candida albicans.
abstract: Membrane reshaping resides at the core of many important cellular processes, and among its mediators are the BAR (Bin, Amphiphysin, Rvs) domain-containing proteins. We have explored the diversity and function of the Rvs BAR proteins in Candida albicans and identified a novel family member, Rvs167-3 (orf19.1861). We show that Rvs167-3 specifically interacts with Rvs162 to form a stable BAR heterodimer able to bind liposomes in vitro. A second, distinct heterodimer is formed by the canonical BAR proteins Rvs161 and Rvs167. Purified Rvs161/Rvs167 complex also binds liposomes, indicating that C. albicans expresses two functional BAR heterodimers. We used live-cell imaging to localize green fluorescent protein (GFP)-tagged Rvs167-3 and Rvs167 and show that both proteins concentrate in small cortical spots. However, while Rvs167 strictly colocalizes with the endocytic marker protein Abp1, we do not observe any colocalization of Rvs167-3 with sites of endocytosis marked by Abp1. Furthermore, the rvs167-3Δ/Δ mutant is not defective in endocytosis and strains lacking Rvs167-3 or its partner Rvs162 do not display increased sensitivity to high salt concentrations or decreased cell wall integrity, phenotypes which have been observed for rvs167Δ/Δ and rvs161Δ/Δ strains and which are linked to endocytosis defects. Taken together, our results indicate different roles for the two BAR heterodimers in C. albicans: the canonical Rvs161/Rvs167 heterodimer functions in endocytosis, whereas the novel Rvs162/Rvs167-3 heterodimer seems not to be involved in this process. Nevertheless, despite their different roles, our phenotypic analysis revealed a genetic interaction between the two BAR heterodimers, suggesting that they may have related but distinct membrane-associated functions.
authors.affiliation: Department of Medical Biochemistry, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: Areti
authors.initials: A
authors.lastname: Gkourtsa
authors.affiliation: Department of Medical Biochemistry, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: Janny
authors.initials: J
authors.lastname: van den Burg
authors.affiliation: Department of Infectious Diseases and Immunology, Utrecht University, Utrecht, The Netherlands.
authors.forename: Karin
authors.initials: K
authors.lastname: Strijbis
authors.affiliation: Department of Medical Biochemistry, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: Teja
authors.initials: T
authors.lastname: Avula
authors.affiliation: Department of Medical Biochemistry, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: Sietske
authors.initials: S
authors.lastname: Bijvoets
authors.affiliation: Department of Medical Biochemistry, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: Dave
authors.initials: D
authors.lastname: Timm
authors.affiliation: Department of Medical Biochemistry, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: Frans
authors.initials: F
authors.lastname: Hochstenbach
authors.affiliation: Department of Medical Biochemistry, Academic Medical Center, Amsterdam, The Netherlands b.distel@amc.uva.nl.
authors.forename: Ben
authors.initials: B
authors.lastname: Distel
mesh_terms: D002176:Candida albicans / Q000235:genetics* / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D003598:Cytoskeletal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004705:Endocytosis; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D055503:Protein Multimerization; D017434:Protein Structure, Tertiary; D021381:Protein Transport
chemical_list: D003598:Cytoskeletal Proteins; D005656:Fungal Proteins; D020033:Protein Isoforms