title: The pathogen-related yeast protein Pry1, a member of the CAP protein superfamily, is a fatty acid-binding protein.
abstract: Members of the CAP superfamily (cysteine-rich secretory proteins,antigen 5, andpathogenesis-related 1 proteins), also known as SCP superfamily (sperm-coatingproteins), have been implicated in many physiological processes, including immune defenses, venom toxicity, and sperm maturation. Their mode of action, however, remains poorly understood. Three proteins of the CAP superfamily, Pry1, -2, and -3 (pathogenrelated inyeast), are encoded in theSaccharomyces cerevisiaegenome. We have shown previously that Pry1 binds cholesterolin vitroand that Pry function is required for sterol secretion in yeast cells, indicating that members of this superfamily may generally bind sterols or related small hydrophobic compounds. On the other hand, tablysin-15, a CAP protein from the horseflyTabanus yao,has been shown to bind leukotrienes and free fatty acidsin vitroTherefore, here we assessed whether the yeast Pry1 protein binds fatty acids. Computational modeling and site-directed mutagenesis indicated that the mode of fatty acid binding is conserved between tablysin-15 and Pry1. Pry1 bound fatty acids with micromolar affinityin vitro, and its function was essential for fatty acid export in cells lacking the acyl-CoA synthetases Faa1 and Faa4. Fatty acid binding of Pry1 is independent of its capacity to bind sterols, and the two sterol- and fatty acid-binding sites are nonoverlapping. These results indicate that some CAP family members, such as Pry1, can bind different lipids, particularly sterols and fatty acids, at distinct binding sites, suggesting that the CAP domain may serve as a stable, secreted protein domain that can accommodate multiple ligand-binding sites.
authors.affiliation: Department of Biology, University of Fribourg, Chemin du Musée 10, 1700 Fribourg, Switzerland.
authors.forename: Rabih
authors.initials: R
authors.lastname: Darwiche
authors.affiliation: Department of Biology, University of Fribourg, Chemin du Musée 10, 1700 Fribourg, Switzerland.
authors.forename: Laurent
authors.initials: L
authors.lastname: Mène-Saffrané
authors.affiliation: Ludwig Center for Cancer Research, University of Lausanne, Biopole III, 1066 Epalinges, Switzerland; Swiss Institute of Bioinformatics (SIB), 1015 Lausanne, Switzerland.
authors.forename: David
authors.initials: D
authors.lastname: Gfeller
authors.affiliation: National School of Tropical Medicine, Baylor College of Medicine, Houston, Texas 77030.
authors.forename: Oluwatoyin A
authors.initials: OA
authors.lastname: Asojo
authors.affiliation: Department of Biology, University of Fribourg, Chemin du Musée 10, 1700 Fribourg, Switzerland. Electronic address: roger.schneiter@unifr.ch.
authors.forename: Roger
authors.initials: R
authors.lastname: Schneiter
mesh_terms: D000214:Acyl Coenzyme A / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D003066:Coenzyme A Ligases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D003198:Computer Simulation; D050556:Fatty Acid-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008840:Microfilament Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed; D000072417:Protein Domains; D012441:Saccharomyces cerevisiae / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D000214:Acyl Coenzyme A; D050556:Fatty Acid-Binding Proteins; D008840:Microfilament Proteins; C000593494:Pry1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D003066:Coenzyme A Ligases; C511244:Faa1 protein, S cerevisiae; C090206:FAA4 protein, S cerevisiae
keywords: CAP protein family; Saccharomyces cerevisiae; acyl-CoA synthetase; cholesterol; fatty acid; fatty acid binding protein; fatty acid transport; secretion; sterol