Osmotic stress activates phosphatidylinositol-3,5-bisphosphate synthesis

Dove, Stephen K.; Cooke, Frank T.; Douglas, Michael E.; Sayers, Lee G.; Parker, Peter J.; Michell, Robert H.

doi:10.1038/36613

Cited by 445 publications

(470 citation statements)

References 26 publications

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“…The mutated cells are binucleate or aploid (FAB [formation of anucleate and binucleate] cells) (11,46). Moreover, hyperosmotic stress provokes a rapid burst of PI(3,5)P 2 synthesis in S. cerevisiae (14). In accordance with this, vps34 mutants of S. cerevisiae and C. albicans show high osmosensitivity (6,23).…”

supporting

confidence: 50%

Defective Hyphal Induction of a Candida albicans Phosphatidylinositol 3-Phosphate 5-Kinase Null Mutant on Solid Media Does Not Lead to Decreased Virulence

Augsten¹,

Hübner²,

Nguyen³

et al. 2002

Infect Immun

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A phosphatidylinositol 3-phosphate [PI(3)P] 5-kinase gene (CaFAB1) of the most important human pathogenic yeast, Candida albicans, was cloned and sequenced. An open reading frame was detected which encodes a 2,369-amino-acid protein with a calculated molecular mass of 268 kDa and a relative isoelectric point of 6.76. This protein exhibits 38% overall amino acid sequence identity with Saccharomyces cerevisiae Fab1p. We localized the CaFAB1 gene on chromosome R. To determine the influence of the PI(3)P 5-kinase CaFab1p on processes involved in C. albicans morphogenesis and pathogenicity, we sequentially disrupted both copies of the gene. Homozygous deletion of C. albicans CaFAB1 resulted in a mutant strain which exhibited defects in morphogenesis. A Cafab1 null mutant had enlarged vacuoles, an acidification defect, and increased generation times and was unable to form hyphae on different solid media. The sensitivities to hyperosmotic and hightemperature stresses, adherence, and virulence compared to those of wild-type strain SC5314 were not affected.Candida albicans is the major fungal pathogen in humans, and its medical significance is increasing (34). This dimorphic yeast is capable of causing life-threatening infections in immunocompromised patients, as well as a variety of mucosal infections in healthy individuals. The present evidence suggests that several factors contribute to the virulence of C. albicans; these factors include the ability to switch between different morphogenetic forms, host epithelial and endothelial cell recognition and adhesion, and secretion of proteinases and phospholipases (12,20,24,29,35). While a number of virulence factors of C. albicans have been characterized, the mechanism which enables this opportunistic fungus to become pathogenic has not been unraveled yet.In eukaryotic cells many biochemical processes are based on the interactions between cytosolic proteins and intracellular membranes. Diverse cellular processes, such as vesicular transport of proteins, signal transduction, cell adhesion, mitogenesis, growth factor downregulation, cytoskeleton rearrangement, and the osmotic stress response, are processes that demand regulated and reversible docking of cytosolic proteins on specific membranes (13,15,44). The proteins bind to cytosolic domains of transmembrane proteins or to the GTP-associated forms of membrane-associated small GTPases. However, it seems that reversible membrane binding of proteins through interactions with specific lipid head groups is an additional mechanism whose importance has increased. In this process phosphatidylinositol (PI) and derivatives of PI that are phosphorylated at positions D-3, D-4, and D-5 play an important role. The different phosphorylated inositols are recognized by different groups of cytosolic proteins, most of which are unknown. However, target proteins of phosphatidylinositol 3-phosphate [PI(3)P] were identified in the yeast Saccharomyces cerevisiae and mammalian cells as proteins that contain a PI(3)P-binding FYVE (Fab1p, YOTB, Vps27...

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supporting

confidence: 50%

Defective Hyphal Induction of a Candida albicans Phosphatidylinositol 3-Phosphate 5-Kinase Null Mutant on Solid Media Does Not Lead to Decreased Virulence

Augsten¹,

Hübner²,

Nguyen³

et al. 2002

Infect Immun

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“…Similar discrepancies have arisen in the study of potential targets for PtdIns(3,5)P 2 , a phosphoinositide involved in intracellular trafficking and vacuolar homeostasis [66,67]. In a similar vein to that described for the FAPP1 PH domain and PtdIns4P, we have been unable, with the vesicle-based techniques described above, to detect PtdIns(3,5)P 2 specificity for two interesting classes of protein: mammalian Vps24p [22] (a component of the ESCRT III complex), and Ent3p/Ent5p from S. cerevisiae [11,68].…”

Section: Ptdins(35)p 2 -Specific Binding Proteinsmentioning

confidence: 86%

Determining selectivity of phosphoinositide-binding domains

Narayan

Lemmon

2006

Methods

119

121

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The burgeoning of phosphoinositide-binding domains and proteins in cellular signaling and trafficking has drawn laboratories from a wide variety of fields into the study of lipid interactions with peripheral membrane proteins. Many different approaches have been developed to assess phosphoinositide binding, some of which are more problematic than others, and some of which can be quantitated more readily than others. With a focus on the methods used in our laboratory, we describe here the considerations that need to be taken into account when establishing -and quantitating -the specific binding of a protein or domain to phosphoinositides in membranes. We also discuss briefly a few examples in which no clear consensus has yet been reached as to the specificity of a given domain or protein because of discrepancies between different commonlyused approaches.

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“…No protein has been shown previously to interact specifically with PtdIns(3,5)P # , and the physiological processes regulated by this lipid are not known. In yeast, PtdIns(3,5)P # is generated in response to osmotic stress [41] by phosphorylation of PtdIns3P at the D-5 position by a kinase termed Fab1 [42,43].…”

Section: Figure 6 Amino Acid Sequence and Tissue Distribution Of Pepp1mentioning

confidence: 99%

Identification of pleckstrin-homology-domain-containing proteins with novel phosphoinositide-binding specificities

et al. 2000

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Osmotic stress activates phosphatidylinositol-3,5-bisphosphate synthesis

Cited by 445 publications

References 26 publications

Defective Hyphal Induction of a Candida albicans Phosphatidylinositol 3-Phosphate 5-Kinase Null Mutant on Solid Media Does Not Lead to Decreased Virulence

Defective Hyphal Induction of a Candida albicans Phosphatidylinositol 3-Phosphate 5-Kinase Null Mutant on Solid Media Does Not Lead to Decreased Virulence

Determining selectivity of phosphoinositide-binding domains

Identification of pleckstrin-homology-domain-containing proteins with novel phosphoinositide-binding specificities

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