Shared functions in vivo of a glycosyl-phosphatidylinositol-linked aspartyl protease, Mkc7, and the proprotein processing protease Kex2 in yeast.

Komano, Hiroto; Fuller, Robert S.

doi:10.1073/pnas.92.23.10752

Cited by 96 publications

(112 citation statements)

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“…Kexin mutants of another fungal pathogen, Candida glabrata, are hypersensitive to Calcoflour, a dye that binds to chitin and is used to identify cell wall mutants (43). S. cerevisiae kex2 deletion mutants grown at low temperatures display defects in cell polarity coincident with delocalization of actin and chitin (16); these phenomena may reflect misprocessing of several cell wall proteins, as judged by altered gel electrophoretic and isoelectric focusing mobilities (44). A C. albicans exoglucansase likely to be involved in cell wall remodeling, Xog1p, is probably processed by Kex2p (45); however, xog1/xog1 mutants do not have the grossly aberrant morphology of kex2/kex2 mutants (46).…”

Section: Discussionmentioning

confidence: 99%

“…Deleting the kexin of the yeast Yarrowia lipolytica abolishes the formation of hyphae (15). kex2-null mutants of the yeast Saccharomyces cerevisiae are viable but exhibit conditional morphological abnormalities (16), defective vacuolar proton-translocating V-ATPase activity (17), cold-sensitive growth (16), and a partial defect in meiosis (genome-www.stanford.edu/Saccharomyces). Genetic data indicate that Kex2p activity somehow may influence the RNA polymerase II complex (18).…”

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confidence: 99%

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Inactivation of Kex2p Diminishes the Virulence of Candida albicans

Newport¹,

Kuo²,

Flattery³

et al. 2003

Journal of Biological Chemistry

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Deletion of the kexin gene (KEX2) in Candida albicanshas a pleiotropic effect on phenotype and virulence due partly to a defect in the expression of two major virulence factors: the secretion of active aspartyl proteinases and the formation of hyphae. kex2/kex2 mutants are highly attenuated in a mouse systemic infection model and persist within cultured macrophages for at least 24 h without causing damage. Pathology is modest, with little disruption of kidney matrix. The infecting mutant cells are largely confined to glomeruli, and are aberrant in morphology. The complex phenotype of the deletion mutants reflects a role for kexin in a wide range of cellular processes. Taking advantage of the specificity of Kex2p cleavage, an algorithm we developed to scan the 9168 open reading frames in Assembly 6 of the C. albicans genome identified 147 potential substrates of Kex2p. These include all previously identified substrates, including eight secreted aspartyl proteinases, the exoglucanase Xog1p, the immunodominant antigen Mp65, and the adhesin Hwp1p. Other putative Kex2p substrates identified include several adhesins, cell wall proteins, and hydrolases previously not implicated in pathogenesis. Kexins also process fungal mating pheromones; a modification of the algorithm identified a putative mating pheromone with structural similarities to Saccharomyces cerevisiae ␣-factor.Serine proteinases of the kexin/subtilisin superfamily activate precursor forms of many exported eukaryotic proteins by specific endoproteolytic cleavage adjacent and C-terminal to dibasic residues. Members of the superfamily play a crucial role in a large and varied set of biological processes in animals, plants, and fungi. In metazoan cells, kexins participate in both the constitutive and regulated secretory pathways, with substrates including hormones, serum proteins, neuropeptides, cell surface receptors, components of the extracellular matrix (ECM), 1 and proteinases, which modify the ECM (1). Furin, a member of the mammalian kexin family, processes several ECM metalloproteinases requisite for the dissemination of cancer cells (2). Kexins have also been suborned to mediate the maturation of viral proteins and bacterial toxins (3). In fungi, kexins cycle between the outer face of the Golgi and the prevacuolar compartment where they process proteins involved in maintenance and remodeling of the cell wall (4, 5), proteins associated with the formation of aerial hyphae (6), ␣-type mating prepropheromones (7), killer toxins (7) , zymogens of secreted proteinases (8 -10), lipases (11), polysaccharide-degrading enzymes (12, 13), and themselves (14). Deleting the kexin of the yeast Yarrowia lipolytica abolishes the formation of hyphae (15). kex2-null mutants of the yeast Saccharomyces cerevisiae are viable but exhibit conditional morphological abnormalities (16), defective vacuolar proton-translocating V-ATPase activity (17), cold-sensitive growth (16), and a partial defect in meiosis (genome-www.stanford.edu/Saccharomyces). Genetic data indicate that ...

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Inactivation of Kex2p Diminishes the Virulence of Candida albicans

Newport¹,

Kuo²,

Flattery³

et al. 2003

Journal of Biological Chemistry

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“…Both have multiple positively charged residues in the Cterminal hydrophobic tail. Surprisingly, the aspartic protease Yps2 has been reported to be cleaved from membranes using a GPI-specific phospholipase (Komano and Fuller, 1995). Possibly, the C-terminal region of Yps2 may contain sequencing errors.…”

Section: Developing a Fungal-specific Gpi Algorithmmentioning

confidence: 99%

Genome‐wide identification of fungal GPI proteins

Groot

Hellingwerf

Klis

2003

Yeast

253

283

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Glycosylphosphatidylinositol-modified (GPI) proteins share structural features that allow their identification using a genomic approach. From the known S. cerevisiae and C. albicans GPI proteins, the following consensus sequence for the GPI attachment site and its downstream region was derived: This consensus sequence, which recognized known GPI proteins from various fungi, was used to screen the genomes of the yeasts S. cerevisiae, C. albicans, Sz. pombe and the filamentous fungus N. crassa for putative GPI proteins. The subsets of proteins so obtained were further screened for the presence of an N-terminal signal sequence for the secretion and absence of internal transmembrane domains. In this way, we identified 66 putative GPI proteins in S. cerevisiae. Some of these are known GPI proteins that were not identified by earlier genomic analyses, indicating that this selection procedure renders a more complete image of the S. cerevisiae GPI proteome. Using the same approach, 104 putative GPI proteins were identified in the human pathogen C. albicans. Among these were the proteins Gas/Phr, Ecm33, Crh and Plb, all members of GPI protein families that are also present in S. cerevisiae. In addition, several proteins and protein families with no significant homology to S. cerevisiae proteins were identified, including the cell wallassociated Als, Csa1/Rbt5, Hwp1/Rbt1 and Hyr1 protein families. In Sz. pombe, which has a low level of (galacto)mannan in the cell wall compared to C. albicans and S. cerevisiae, only 33 GPI candidates were identified and in N. crassa 97. BLAST searches revealed that about half of the putative GPI proteins that were identified in Sz. pombe and N. crassa are homologous to known or putative GPI proteins from other fungi. We conclude that our algorithm is selective and can also be used for GPI protein identification in other fungi.

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“…The SUC2 strain CRY2 was provided by Dr. Robert Fuller (Komano and Fuller, 1995). The suc2-null strain SEY6210 was provided by Dr. Scott Emr (Robinson et al, 1988).…”

Section: Yeast Strainsmentioning

confidence: 99%

Yeast Genes Controlling Responses to Topogenic Signals in a Model Transmembrane Protein

Tipper

Harley

2002

MBoC

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Yeast protein insertion orientation (PIO) mutants were isolated by selecting for growth on sucrose in cells in which the only source of invertase is a C-terminal fusion to a transmembrane protein.Only the fraction with an exocellular C terminus can be processed to secreted invertase and this fraction is constrained to 2-3% by a strong charge difference signal. Identified pio mutants increased this to 9 -12%. PIO1 is SPF1, encoding a P-type ATPase located in the endoplasmic reticulum (ER) or Golgi. spf1-null mutants are modestly sensitive to EGTA. Sensitivity is considerably greater in an spf1 pmr1 double mutant, although PIO is not further disturbed. Pmr1p is the Golgi Ca 2ϩ ATPase and Spf1p may be the equivalent ER pump. PIO2 is STE24, a metalloprotease anchored in the ER membrane. Like Spf1p, Ste24p is expressed in all yeast cell types and belongs to a highly conserved protein family. The effects of ste24-and spf1-null mutations on invertase secretion are additive, cell generation time is increased 60%, and cells become sensitive to cold and to heat shock. Ste24p and Rce1p cleave the C-AAX bond of farnesylated CAAX box proteins. The closest paralog of SPF1 is YOR291w. Neither rce1-null nor yor291w-null mutations affected PIO or the phenotype of spf1-or ste24-null mutants. Mutations in PIO3 (unidentified) cause a weaker Pio phenotype, enhanced by a null mutation in BMH1, one of two yeast 14-3-3 proteins.

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Shared functions in vivo of a glycosyl-phosphatidylinositol-linked aspartyl protease, Mkc7, and the proprotein processing protease Kex2 in yeast.

Cited by 96 publications

References 37 publications

Inactivation of Kex2p Diminishes the Virulence of Candida albicans

Inactivation of Kex2p Diminishes the Virulence of Candida albicans

Genome‐wide identification of fungal GPI proteins

Yeast Genes Controlling Responses to Topogenic Signals in a Model Transmembrane Protein

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