Rac1 and Cdc42 regulate hyphal growth and cytokinesis in the dimorphic fungus Ustilago maydis

被引:129
作者
Mahlert, M [1 ]
Leveleki, L [1 ]
Hlubek, A [1 ]
Sandrock, B [1 ]
Bölker, M [1 ]
机构
[1] Univ Marburg, Fachbereich Biol, D-35032 Marburg, Germany
关键词
D O I
10.1111/j.1365-2958.2005.04952.x
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Small GTP-binding proteins of the highly conserved Rho family act as molecular switches regulating cell signalling, cytoskeletal organization and vesicle trafficking in eukaryotic cells. Here we show that in the dimorphic plant pathogenic fungus Ustilago maydis deletion of either cdc42 or rac1 results in loss of virulence but does not interfere with viability. Cells deleted for cdc42 display a cell separation defect during budding. We have previously shown that the Rho-specific guanine nucleotide exchange factor (GEF) Don1 is required for cell separation in U. maydis. Expression of constitutive active Cdc42 rescues the phenotype of don1 mutant cells indicating that Don1 triggers cell separation by activating Cdc42. Deletion of rac1 affects cellular morphology and interferes with hyphal growth, whereas overexpression of wild-type Rac1 induces filament formation in haploid cells. This indicates that Rac1 is both necessary and sufficient for the dimorphic switch from budding to hyphal growth. Cdc42 and Rac1 share at least one common essential function because depletion of both Rac1 and Cdc42 is lethal. Expression of constitutively active Rac1(Q61L) is lethal and results in swollen cells with a large vacuole. The morphological phenotype, but not lethality is suppressed in cla4 mutant cells suggesting that the PAK family kinase Cla4 acts as a downstream effector of Rac1.
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收藏
页码:567 / 578
页数:12
相关论文
共 59 条
[1]   CDC42 AND CDC43, 2 ADDITIONAL GENES INVOLVED IN BUDDING AND THE ESTABLISHMENT OF CELL POLARITY IN THE YEAST SACCHAROMYCES-CEREVISIAE [J].
ADAMS, AEM ;
JOHNSON, DI ;
LONGNECKER, RM ;
SLOAT, BF ;
PRINGLE, JR .
JOURNAL OF CELL BIOLOGY, 1990, 111 (01) :131-142
[2]   Genetics of Ustilago maydis, a fungal pathogen that induces tumors in maize [J].
Banuett, F .
ANNUAL REVIEW OF GENETICS, 1995, 29 :179-208
[3]   GAP control: regulating the regulators of small GTPases [J].
Bernards, A ;
Settleman, J .
TRENDS IN CELL BIOLOGY, 2004, 14 (07) :377-385
[4]   REGULATION OF THE PHAGOCYTE RESPIRATORY BURST BY SMALL GTP-BINDING PROTEINS [J].
BOKOCH, GM .
TRENDS IN CELL BIOLOGY, 1995, 5 (03) :109-113
[5]  
BOLKER M, 1995, CAN J BOT, V73, pS320
[6]  
Bölker M, 2001, MICROBIOL-SGM, V147, P1395, DOI 10.1099/00221287-147-6-1395
[7]   Isolation of a carbon source-regulated gene from Ustilago maydis [J].
Bottin, A ;
Kamper, J ;
Kahmann, R .
MOLECULAR AND GENERAL GENETICS, 1996, 253 (03) :342-352
[8]   The Ras and Rho GTPases genetically interact to co-ordinately regulate cell polarity during development in Penicillium marneffei [J].
Boyce, KJ ;
Hynes, MJ ;
Andrianopoulos, A .
MOLECULAR MICROBIOLOGY, 2005, 55 (05) :1487-1501
[9]   Control of morphogenesis and actin localization by the Penicillium marneffei RAC homolog [J].
Boyce, KJ ;
Hynes, MJ ;
Andrianopoulos, A .
JOURNAL OF CELL SCIENCE, 2003, 116 (07) :1249-1260
[10]   Identification of genes in the bW/bE regulatory cascade in Ustilago maydis [J].
Brachmann, A ;
Weinzierl, G ;
Kämper, J ;
Kahmann, R .
MOLECULAR MICROBIOLOGY, 2001, 42 (04) :1047-1063