Rab27a targeting to melanosomes requires nucleotide exchange but not effector binding

Detalhes bibliográficos
Autor(a) principal: Tarafder, Abul K.
Data de Publicação: 2011
Outros Autores: Wasmeier, Christina, Figueiredo, Ana C., Booth, Antonia E.G., Orihara, Asumi, Ramalho, Jose S., Hume, Alistair N., Seabra, Miguel C.
Tipo de documento: Artigo
Idioma: eng
Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
Texto Completo: http://hdl.handle.net/10362/146412
Resumo: Rab GTPases are important determinants of organelle identity and regulators of vesicular transport pathways. Consequently, each Rab occupies a highly specific subcellular localization. However, the precise mechanisms governing Rab targeting remain unclear. Guanine nucleotide exchange factors (GEFs), putative membrane-resident targeting factors and effector binding have all been implicated as critical regulators of Rab targeting. Here, we address these issues using Rab27a targeting to melanosomes as a model system. Rab27a regulates motility of lysosome-related organelles and secretory granules. Its effectors have been characterized extensively, and we have identified Rab3GEP as the non-redundant Rab27a GEF in melanocytes (Figueiredo AC et al. Rab3GEP is the non-redundant guanine nucleotide exchange factor for Rab27a in melanocytes. J Biol Chem 2008;283:23209-23216). Using Rab27a mutants that show impaired binding to representatives of all four Rab27a effector subgroups, we present evidence that effector binding is not essential for targeting of Rab27a to melanosomes. In contrast, we observed that knockdown of Rab3GEP resulted in mis-targeting of Rab27a, suggesting that Rab3GEP activity is required for correct targeting of Rab27a. However, the identification of Rab27a mutants that undergo efficient GDP/GTP exchange in the presence of Rab3GEP in vitro but are mis-targeted in a cellular context indicates that nucleotide loading is not the sole determinant of subcellular targeting of Rab27a. Our data support a model in which exchange activity, but not effector binding, represents one essential factor that contributes to membrane targeting of Rab proteins.
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spelling Rab27a targeting to melanosomes requires nucleotide exchange but not effector bindingEffectorsGuanine nucleotide exchange factorMelanosomeRabTargetingStructural BiologyBiochemistryMolecular BiologyGeneticsCell BiologyRab GTPases are important determinants of organelle identity and regulators of vesicular transport pathways. Consequently, each Rab occupies a highly specific subcellular localization. However, the precise mechanisms governing Rab targeting remain unclear. Guanine nucleotide exchange factors (GEFs), putative membrane-resident targeting factors and effector binding have all been implicated as critical regulators of Rab targeting. Here, we address these issues using Rab27a targeting to melanosomes as a model system. Rab27a regulates motility of lysosome-related organelles and secretory granules. Its effectors have been characterized extensively, and we have identified Rab3GEP as the non-redundant Rab27a GEF in melanocytes (Figueiredo AC et al. Rab3GEP is the non-redundant guanine nucleotide exchange factor for Rab27a in melanocytes. J Biol Chem 2008;283:23209-23216). Using Rab27a mutants that show impaired binding to representatives of all four Rab27a effector subgroups, we present evidence that effector binding is not essential for targeting of Rab27a to melanosomes. In contrast, we observed that knockdown of Rab3GEP resulted in mis-targeting of Rab27a, suggesting that Rab3GEP activity is required for correct targeting of Rab27a. However, the identification of Rab27a mutants that undergo efficient GDP/GTP exchange in the presence of Rab3GEP in vitro but are mis-targeted in a cellular context indicates that nucleotide loading is not the sole determinant of subcellular targeting of Rab27a. Our data support a model in which exchange activity, but not effector binding, represents one essential factor that contributes to membrane targeting of Rab proteins.NOVA Medical School|Faculdade de Ciências Médicas (NMS|FCM)Centro de Estudos de Doenças Crónicas (CEDOC)RUNTarafder, Abul K.Wasmeier, ChristinaFigueiredo, Ana C.Booth, Antonia E.G.Orihara, AsumiRamalho, Jose S.Hume, Alistair N.Seabra, Miguel C.2022-12-19T22:13:58Z2011-082011-08-01T00:00:00Zinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/article11application/pdfhttp://hdl.handle.net/10362/146412eng1398-9219PURE: 48399707https://doi.org/10.1111/j.1600-0854.2011.01216.xinfo:eu-repo/semantics/openAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2024-03-11T05:27:29Zoai:run.unl.pt:10362/146412Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-20T03:52:37.288068Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse
dc.title.none.fl_str_mv Rab27a targeting to melanosomes requires nucleotide exchange but not effector binding
title Rab27a targeting to melanosomes requires nucleotide exchange but not effector binding
spellingShingle Rab27a targeting to melanosomes requires nucleotide exchange but not effector binding
Tarafder, Abul K.
Effectors
Guanine nucleotide exchange factor
Melanosome
Rab
Targeting
Structural Biology
Biochemistry
Molecular Biology
Genetics
Cell Biology
title_short Rab27a targeting to melanosomes requires nucleotide exchange but not effector binding
title_full Rab27a targeting to melanosomes requires nucleotide exchange but not effector binding
title_fullStr Rab27a targeting to melanosomes requires nucleotide exchange but not effector binding
title_full_unstemmed Rab27a targeting to melanosomes requires nucleotide exchange but not effector binding
title_sort Rab27a targeting to melanosomes requires nucleotide exchange but not effector binding
author Tarafder, Abul K.
author_facet Tarafder, Abul K.
Wasmeier, Christina
Figueiredo, Ana C.
Booth, Antonia E.G.
Orihara, Asumi
Ramalho, Jose S.
Hume, Alistair N.
Seabra, Miguel C.
author_role author
author2 Wasmeier, Christina
Figueiredo, Ana C.
Booth, Antonia E.G.
Orihara, Asumi
Ramalho, Jose S.
Hume, Alistair N.
Seabra, Miguel C.
author2_role author
author
author
author
author
author
author
dc.contributor.none.fl_str_mv NOVA Medical School|Faculdade de Ciências Médicas (NMS|FCM)
Centro de Estudos de Doenças Crónicas (CEDOC)
RUN
dc.contributor.author.fl_str_mv Tarafder, Abul K.
Wasmeier, Christina
Figueiredo, Ana C.
Booth, Antonia E.G.
Orihara, Asumi
Ramalho, Jose S.
Hume, Alistair N.
Seabra, Miguel C.
dc.subject.por.fl_str_mv Effectors
Guanine nucleotide exchange factor
Melanosome
Rab
Targeting
Structural Biology
Biochemistry
Molecular Biology
Genetics
Cell Biology
topic Effectors
Guanine nucleotide exchange factor
Melanosome
Rab
Targeting
Structural Biology
Biochemistry
Molecular Biology
Genetics
Cell Biology
description Rab GTPases are important determinants of organelle identity and regulators of vesicular transport pathways. Consequently, each Rab occupies a highly specific subcellular localization. However, the precise mechanisms governing Rab targeting remain unclear. Guanine nucleotide exchange factors (GEFs), putative membrane-resident targeting factors and effector binding have all been implicated as critical regulators of Rab targeting. Here, we address these issues using Rab27a targeting to melanosomes as a model system. Rab27a regulates motility of lysosome-related organelles and secretory granules. Its effectors have been characterized extensively, and we have identified Rab3GEP as the non-redundant Rab27a GEF in melanocytes (Figueiredo AC et al. Rab3GEP is the non-redundant guanine nucleotide exchange factor for Rab27a in melanocytes. J Biol Chem 2008;283:23209-23216). Using Rab27a mutants that show impaired binding to representatives of all four Rab27a effector subgroups, we present evidence that effector binding is not essential for targeting of Rab27a to melanosomes. In contrast, we observed that knockdown of Rab3GEP resulted in mis-targeting of Rab27a, suggesting that Rab3GEP activity is required for correct targeting of Rab27a. However, the identification of Rab27a mutants that undergo efficient GDP/GTP exchange in the presence of Rab3GEP in vitro but are mis-targeted in a cellular context indicates that nucleotide loading is not the sole determinant of subcellular targeting of Rab27a. Our data support a model in which exchange activity, but not effector binding, represents one essential factor that contributes to membrane targeting of Rab proteins.
publishDate 2011
dc.date.none.fl_str_mv 2011-08
2011-08-01T00:00:00Z
2022-12-19T22:13:58Z
dc.type.status.fl_str_mv info:eu-repo/semantics/publishedVersion
dc.type.driver.fl_str_mv info:eu-repo/semantics/article
format article
status_str publishedVersion
dc.identifier.uri.fl_str_mv http://hdl.handle.net/10362/146412
url http://hdl.handle.net/10362/146412
dc.language.iso.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv 1398-9219
PURE: 48399707
https://doi.org/10.1111/j.1600-0854.2011.01216.x
dc.rights.driver.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv 11
application/pdf
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repository.name.fl_str_mv Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação
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