title: Pn-AMP1, a plant defense protein, induces actin depolarization in yeasts.
abstract: Pn-AMP1, Pharbitis nil antimicrobial peptide 1, is a small cysteine-rich peptide implicated in host-plant defense. We show here that Pn-AMP1 causes depolarization of the actin cytoskeleton in Saccharomyces cerevisiae and Candida albicans. Pn-AMP1 induces rapid depolarization of actin cables and patches within 15 min. Increased osmolarity or temperature induces transient actin depolarization and results in increased sensitivity to Pn-AMP1, while cells conditioned to these stresses show less sensitivity. Mutations in components of a cell wall integrity pathway (Wsc1p, Rom2p, Bck1p and Mpk1p), which regulate actin repolarization, result in increased sensitivity to Pn-AMP1. A genetic screen reveals that mutations in components of the alpha-1,6-mannosyltransferase complex (Mnn10p, Mnn11p and Och1p), which regulate mannosylation of cell wall proteins, confer resistance to Pn-AMP1. FITC-conjugated Pn-AMP1 localizes to the outer surface of the cell with no significant staining observed in spheroplasts. Taken together, these results indicate that cell wall proteins are determinants of resistance to Pn-AMP1, and the ability of a plant defense protein to induce actin depolarization is important for its antifungal activity.
authors.affiliation: Division of Applied Life Science (BK21 program), PMBBRC, and Environmental Biotechnology National Core Research Center, Graduate School of Gyeongsang National University, Jinju 660-701, Korea.
authors.forename: Ja Choon
authors.initials: JC
authors.lastname: Koo
authors.forename: Boyoung
authors.initials: B
authors.lastname: Lee
authors.forename: Michael E
authors.initials: ME
authors.lastname: Young
authors.forename: Sung Chul
authors.initials: SC
authors.lastname: Koo
authors.forename: John A
authors.initials: JA
authors.lastname: Cooper
authors.forename: Dongwon
authors.initials: D
authors.lastname: Baek
authors.forename: Chae Oh
authors.initials: CO
authors.lastname: Lim
authors.forename: Sang Yeol
authors.initials: SY
authors.lastname: Lee
authors.forename: Dae-Jin
authors.initials: DJ
authors.lastname: Yun
authors.forename: Moo Je
authors.initials: MJ
authors.lastname: Cho
mesh_terms: D000199:Actins / Q000187:drug effects / Q000378:metabolism*; D000935:Antifungal Agents / Q000494:pharmacology; D002176:Candida albicans / Q000254:growth & development / Q000378:metabolism*; D002473:Cell Wall / Q000378:metabolism; D002478:Cells, Cultured; D003599:Cytoskeleton / Q000378:metabolism*; D006358:Hot Temperature; D008562:Membrane Glycoproteins / Q000378:metabolism; D008954:Models, Biological; D009154:Mutation; D010940:Plant Proteins / Q000494:pharmacology*; D012441:Saccharomyces cerevisiae / Q000254:growth & development / Q000378:metabolism*; D012680:Sensitivity and Specificity
chemical_list: D000199:Actins; D000935:Antifungal Agents; D008562:Membrane Glycoproteins; D010940:Plant Proteins; C111188:antimicrobial peptide, Pharbitis; C025363:mannoproteins