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Probing the importance and potential roles of the binding of the PH-domain protein Boi1 to acidic phospholipids

BACKGROUND: The related proteins Boi1 and Boi2, which appear to promote polarized growth in S. cerevisiae, both contain a PH (pleckstrin homology) and an SH3 (src homology 3) domain. Previously, we gained evidence that a PH domain-bearing segment of Boi1, which we call Boi1-PH, is sufficient and nec...

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Autores principales: Hallett, Mark A, Lo, H Shuen, Bender, Alan
Formato: Texto
Lenguaje:English
Publicado: BioMed Central 2002
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC117597/
https://www.ncbi.nlm.nih.gov/pubmed/12097146
http://dx.doi.org/10.1186/1471-2121-3-16
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author Hallett, Mark A
Lo, H Shuen
Bender, Alan
author_facet Hallett, Mark A
Lo, H Shuen
Bender, Alan
author_sort Hallett, Mark A
collection PubMed
description BACKGROUND: The related proteins Boi1 and Boi2, which appear to promote polarized growth in S. cerevisiae, both contain a PH (pleckstrin homology) and an SH3 (src homology 3) domain. Previously, we gained evidence that a PH domain-bearing segment of Boi1, which we call Boi1-PH, is sufficient and necessary for function. In the current study, we investigate the binding of Boi1's PH domain to the acidic phospholipids PIP(2) (phosphatidylinositol-4,5-bisphosphate) and PS (phosphatidylserine). RESULTS: Boi1-PH co-sediments with PS vesicles. It does so more readily when these vesicles contain a small amount of PIP(2). Boi1-PH is degraded in yeast extracts in a manner that is stimulated by PIP(2). Amino-acid substitutions that diminish binding to PIP(2) and PS impair Boi1 function. Fusion to a myristoyl group-accepting sequence improves to different degrees the ability of these different mutant versions of Boi1-PH to function. Boi1 and Boi2 are localized to the periphery of buds during much of the budding cycle and to necks late in the cell cycle. Amino-acid substitutions that diminish binding to PIP(2) and PS impair localization of Boi1 to the bud, but do not affect the localization of Boi1 to the neck. Conversely, a mutation in the SH3 domain prevents the localization of Boi1 to the neck, but does not impair localization to the bud. CONCLUSIONS: Boi1's PH domain binds to acidic phospholipids, and this binding appears to be important for Boi1 function. The main role of binding to PS may simply be to promote the association of the PH domain with membrane. The higher-affinity binding to PIP(2), which apparently promotes a conformational change in the PH domain, may play an important additional role. Boi1 and Boi2 are localized to sites of polarized growth. Whereas the SH3 domain is needed for localization of Boi1 to the neck, the phospholipid-binding portion of the PH domain is important for localization to the bud.
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spelling pubmed-1175972002-08-01 Probing the importance and potential roles of the binding of the PH-domain protein Boi1 to acidic phospholipids Hallett, Mark A Lo, H Shuen Bender, Alan BMC Cell Biol Research Article BACKGROUND: The related proteins Boi1 and Boi2, which appear to promote polarized growth in S. cerevisiae, both contain a PH (pleckstrin homology) and an SH3 (src homology 3) domain. Previously, we gained evidence that a PH domain-bearing segment of Boi1, which we call Boi1-PH, is sufficient and necessary for function. In the current study, we investigate the binding of Boi1's PH domain to the acidic phospholipids PIP(2) (phosphatidylinositol-4,5-bisphosphate) and PS (phosphatidylserine). RESULTS: Boi1-PH co-sediments with PS vesicles. It does so more readily when these vesicles contain a small amount of PIP(2). Boi1-PH is degraded in yeast extracts in a manner that is stimulated by PIP(2). Amino-acid substitutions that diminish binding to PIP(2) and PS impair Boi1 function. Fusion to a myristoyl group-accepting sequence improves to different degrees the ability of these different mutant versions of Boi1-PH to function. Boi1 and Boi2 are localized to the periphery of buds during much of the budding cycle and to necks late in the cell cycle. Amino-acid substitutions that diminish binding to PIP(2) and PS impair localization of Boi1 to the bud, but do not affect the localization of Boi1 to the neck. Conversely, a mutation in the SH3 domain prevents the localization of Boi1 to the neck, but does not impair localization to the bud. CONCLUSIONS: Boi1's PH domain binds to acidic phospholipids, and this binding appears to be important for Boi1 function. The main role of binding to PS may simply be to promote the association of the PH domain with membrane. The higher-affinity binding to PIP(2), which apparently promotes a conformational change in the PH domain, may play an important additional role. Boi1 and Boi2 are localized to sites of polarized growth. Whereas the SH3 domain is needed for localization of Boi1 to the neck, the phospholipid-binding portion of the PH domain is important for localization to the bud. BioMed Central 2002-06-27 /pmc/articles/PMC117597/ /pubmed/12097146 http://dx.doi.org/10.1186/1471-2121-3-16 Text en Copyright © 2002 Hallett et al; licensee BioMed Central Ltd. This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original URL.
spellingShingle Research Article
Hallett, Mark A
Lo, H Shuen
Bender, Alan
Probing the importance and potential roles of the binding of the PH-domain protein Boi1 to acidic phospholipids
title Probing the importance and potential roles of the binding of the PH-domain protein Boi1 to acidic phospholipids
title_full Probing the importance and potential roles of the binding of the PH-domain protein Boi1 to acidic phospholipids
title_fullStr Probing the importance and potential roles of the binding of the PH-domain protein Boi1 to acidic phospholipids
title_full_unstemmed Probing the importance and potential roles of the binding of the PH-domain protein Boi1 to acidic phospholipids
title_short Probing the importance and potential roles of the binding of the PH-domain protein Boi1 to acidic phospholipids
title_sort probing the importance and potential roles of the binding of the ph-domain protein boi1 to acidic phospholipids
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC117597/
https://www.ncbi.nlm.nih.gov/pubmed/12097146
http://dx.doi.org/10.1186/1471-2121-3-16
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