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Component Specificity for the Thylakoidal Sec and Delta Ph–Dependent Protein Transport Pathways

Prokaryotes and prokaryote-derived thylakoid membranes of chloroplasts share multiple, evolutionarily conserved pathways for protein export. These include the Sec, signal recognition particle (SRP), and Delta pH/Tat systems. Little is known regarding the thylakoid membrane components involved in the...

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Autores principales: Mori, Hiroki, Summer, Elizabeth J., Ma, Xianyue, Cline, Kenneth
Formato: Texto
Lenguaje:English
Publicado: The Rockefeller University Press 1999
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2199744/
https://www.ncbi.nlm.nih.gov/pubmed/10402459
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author Mori, Hiroki
Summer, Elizabeth J.
Ma, Xianyue
Cline, Kenneth
author_facet Mori, Hiroki
Summer, Elizabeth J.
Ma, Xianyue
Cline, Kenneth
author_sort Mori, Hiroki
collection PubMed
description Prokaryotes and prokaryote-derived thylakoid membranes of chloroplasts share multiple, evolutionarily conserved pathways for protein export. These include the Sec, signal recognition particle (SRP), and Delta pH/Tat systems. Little is known regarding the thylakoid membrane components involved in these pathways. We isolated a cDNA clone to a novel component of the Delta pH pathway, Tha4, and prepared antibodies against pea Tha4, against maize Hcf106, a protein implicated in Delta pH pathway transport by genetic studies, and against cpSecY, the thylakoid homologue of the bacterial SecY translocon protein. These components were localized to the nonappressed thylakoid membranes. Tha4 and Hcf106 were present in ∼10-fold excess over active translocation sites. Antibodies to either Tha4 or Hcf106 inhibited translocation of four known Delta pH pathway substrate proteins, but not of Sec pathway or SRP pathway substrates. This suggests that Tha4 and Hcf106 operate either in series or as subunits of a heteromultimeric complex. cpSecY antibodies inhibited translocation of Sec pathway substrates but not of Delta pH or SRP pathway substrates. These studies provide the first biochemical evidence that Tha4 and Hcf106 are specific components of the Delta pH pathway and provide one line of evidence that cpSecY is used specifically by the Sec pathway.
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spelling pubmed-21997442008-05-01 Component Specificity for the Thylakoidal Sec and Delta Ph–Dependent Protein Transport Pathways Mori, Hiroki Summer, Elizabeth J. Ma, Xianyue Cline, Kenneth J Cell Biol Original Article Prokaryotes and prokaryote-derived thylakoid membranes of chloroplasts share multiple, evolutionarily conserved pathways for protein export. These include the Sec, signal recognition particle (SRP), and Delta pH/Tat systems. Little is known regarding the thylakoid membrane components involved in these pathways. We isolated a cDNA clone to a novel component of the Delta pH pathway, Tha4, and prepared antibodies against pea Tha4, against maize Hcf106, a protein implicated in Delta pH pathway transport by genetic studies, and against cpSecY, the thylakoid homologue of the bacterial SecY translocon protein. These components were localized to the nonappressed thylakoid membranes. Tha4 and Hcf106 were present in ∼10-fold excess over active translocation sites. Antibodies to either Tha4 or Hcf106 inhibited translocation of four known Delta pH pathway substrate proteins, but not of Sec pathway or SRP pathway substrates. This suggests that Tha4 and Hcf106 operate either in series or as subunits of a heteromultimeric complex. cpSecY antibodies inhibited translocation of Sec pathway substrates but not of Delta pH or SRP pathway substrates. These studies provide the first biochemical evidence that Tha4 and Hcf106 are specific components of the Delta pH pathway and provide one line of evidence that cpSecY is used specifically by the Sec pathway. The Rockefeller University Press 1999-07-12 /pmc/articles/PMC2199744/ /pubmed/10402459 Text en © 1999 The Rockefeller University Press This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/4.0/).
spellingShingle Original Article
Mori, Hiroki
Summer, Elizabeth J.
Ma, Xianyue
Cline, Kenneth
Component Specificity for the Thylakoidal Sec and Delta Ph–Dependent Protein Transport Pathways
title Component Specificity for the Thylakoidal Sec and Delta Ph–Dependent Protein Transport Pathways
title_full Component Specificity for the Thylakoidal Sec and Delta Ph–Dependent Protein Transport Pathways
title_fullStr Component Specificity for the Thylakoidal Sec and Delta Ph–Dependent Protein Transport Pathways
title_full_unstemmed Component Specificity for the Thylakoidal Sec and Delta Ph–Dependent Protein Transport Pathways
title_short Component Specificity for the Thylakoidal Sec and Delta Ph–Dependent Protein Transport Pathways
title_sort component specificity for the thylakoidal sec and delta ph–dependent protein transport pathways
topic Original Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2199744/
https://www.ncbi.nlm.nih.gov/pubmed/10402459
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