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Efficient endosomal localization of major histocompatibility complex class II-invariant chain complexes requires multimerization of the invariant chain targeting sequence
During biosynthesis, MHC class II-invariant chain complexes are transported into endosomal compartments where invariant chain (Ii) is degraded and class II encounters antigenic peptides. One of the signals that determines this intracellular transport route has been localized to the cytosolic domain...
Formato: | Texto |
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Lenguaje: | English |
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The Rockefeller University Press
1995
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2120468/ https://www.ncbi.nlm.nih.gov/pubmed/7775569 |
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collection | PubMed |
description | During biosynthesis, MHC class II-invariant chain complexes are transported into endosomal compartments where invariant chain (Ii) is degraded and class II encounters antigenic peptides. One of the signals that determines this intracellular transport route has been localized to the cytosolic domain of Ii. Deletion of this signal disrupts endosomal targeting and results in the stable expression of class II-Ii complexes at the surface. In this paper we have examined the role of Ii trimerization on the generation of this endosomal localization signal. In L cell transfectants expressing class II and both wild type Ii and a truncated form of Ii that lacks this endosomal localization signal, Ii was found to form multimers which could contain both wild type and truncated Ii. The multimers were not large aggregates but were found to be discrete complexes, probably the nine molecule class II-Ii complex that has been observed in human B cells. The co-expression of truncated Ii allowed for cell surface expression of a subset of wild type Ii. This surface-expressed wild type Ii associated with truncated Ii in multimers at a 2:1 ratio, indicating that these trimers contain two truncated and one wild type Ii molecule. These data suggest a division in trafficking of Ii trimers: if two wild type Ii molecules are present, the complex is transported to and rapidly degraded in endosomes, whereas the presence of only one wild type Ii results in trafficking and expression of the heterotrimer on the cell surface. Following surface arrival, complexes containing only a single wild type Ii molecule are internalized more rapidly and have a shorter half-life than complexes containing only truncated Ii molecules. These data suggest that although a single Ii cytosolic domain can function as a plasma membrane internalization signal, multimerization of Ii is required for efficient Golgi complex to endosome targeting of class II- Ii complexes. |
format | Text |
id | pubmed-2120468 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 1995 |
publisher | The Rockefeller University Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-21204682008-05-01 Efficient endosomal localization of major histocompatibility complex class II-invariant chain complexes requires multimerization of the invariant chain targeting sequence J Cell Biol Articles During biosynthesis, MHC class II-invariant chain complexes are transported into endosomal compartments where invariant chain (Ii) is degraded and class II encounters antigenic peptides. One of the signals that determines this intracellular transport route has been localized to the cytosolic domain of Ii. Deletion of this signal disrupts endosomal targeting and results in the stable expression of class II-Ii complexes at the surface. In this paper we have examined the role of Ii trimerization on the generation of this endosomal localization signal. In L cell transfectants expressing class II and both wild type Ii and a truncated form of Ii that lacks this endosomal localization signal, Ii was found to form multimers which could contain both wild type and truncated Ii. The multimers were not large aggregates but were found to be discrete complexes, probably the nine molecule class II-Ii complex that has been observed in human B cells. The co-expression of truncated Ii allowed for cell surface expression of a subset of wild type Ii. This surface-expressed wild type Ii associated with truncated Ii in multimers at a 2:1 ratio, indicating that these trimers contain two truncated and one wild type Ii molecule. These data suggest a division in trafficking of Ii trimers: if two wild type Ii molecules are present, the complex is transported to and rapidly degraded in endosomes, whereas the presence of only one wild type Ii results in trafficking and expression of the heterotrimer on the cell surface. Following surface arrival, complexes containing only a single wild type Ii molecule are internalized more rapidly and have a shorter half-life than complexes containing only truncated Ii molecules. These data suggest that although a single Ii cytosolic domain can function as a plasma membrane internalization signal, multimerization of Ii is required for efficient Golgi complex to endosome targeting of class II- Ii complexes. The Rockefeller University Press 1995-06-01 /pmc/articles/PMC2120468/ /pubmed/7775569 Text en 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 | Articles Efficient endosomal localization of major histocompatibility complex class II-invariant chain complexes requires multimerization of the invariant chain targeting sequence |
title | Efficient endosomal localization of major histocompatibility complex class II-invariant chain complexes requires multimerization of the invariant chain targeting sequence |
title_full | Efficient endosomal localization of major histocompatibility complex class II-invariant chain complexes requires multimerization of the invariant chain targeting sequence |
title_fullStr | Efficient endosomal localization of major histocompatibility complex class II-invariant chain complexes requires multimerization of the invariant chain targeting sequence |
title_full_unstemmed | Efficient endosomal localization of major histocompatibility complex class II-invariant chain complexes requires multimerization of the invariant chain targeting sequence |
title_short | Efficient endosomal localization of major histocompatibility complex class II-invariant chain complexes requires multimerization of the invariant chain targeting sequence |
title_sort | efficient endosomal localization of major histocompatibility complex class ii-invariant chain complexes requires multimerization of the invariant chain targeting sequence |
topic | Articles |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2120468/ https://www.ncbi.nlm.nih.gov/pubmed/7775569 |