The endoplasmic reticulum-associated protein, OS-9, behaves as a lectin in targeting the immature calcium-sensing receptor
The mechanisms responsible for the processing and quality control of the calcium-sensing receptor (CaSR) in the endoplasmic reticulum (ER) are largely unknown. In a yeast two-hybrid screen of the CaSR C-terminal tail (residues 865-1078), we identified osteosarcoma-9 (OS-9) protein as a binding partn...
| Main Authors: | , , , , , , , , , |
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| Format: | Journal Article |
| Published: |
John Wiley & Sons, Inc.
2017
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| Online Access: | http://hdl.handle.net/20.500.11937/53988 |
| _version_ | 1848759276012568576 |
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| author | Ward, B. Rea, S. Magno, A. Pedersen, B. Brown, S. Mullin, S. Arulpragasam, Ajanthy Ingley, E. Conigrave, A. Ratajczak, T. |
| author_facet | Ward, B. Rea, S. Magno, A. Pedersen, B. Brown, S. Mullin, S. Arulpragasam, Ajanthy Ingley, E. Conigrave, A. Ratajczak, T. |
| author_sort | Ward, B. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | The mechanisms responsible for the processing and quality control of the calcium-sensing receptor (CaSR) in the endoplasmic reticulum (ER) are largely unknown. In a yeast two-hybrid screen of the CaSR C-terminal tail (residues 865-1078), we identified osteosarcoma-9 (OS-9) protein as a binding partner. OS-9 is an ER-resident lectin that targets misfolded glycoproteins to the ER-associated degradation (ERAD) pathway through recognition of specific N-glycans by its mannose-6-phosphate receptor homology (MRH) domain. We show by confocal microscopy that the CaSR and OS-9 co-localize in the ER in COS-1 cells. In immunoprecipitation studies with co-expressed OS-9 and CaSR, OS-9 specifically bound the immature form of wild-type CaSR in the ER. OS-9 also bound the immature forms of a CaSR C-terminal deletion mutant and a C677A mutant that remains trapped in the ER, although binding to neither mutant was favored over wild-type receptor. OS-9 binding to immature CaSR required the MRH domain of OS-9 indicating that OS-9 acts as a lectin most likely to target misfolded CaSR to ERAD. Our results also identify two distinct binding interactions between OS-9 and the CaSR, one involving both C-terminal domains of the two proteins and the other involving both N-terminal domains. This suggests the possibility of more than one functional interaction between OS-9 and the CaSR. When we investigated the functional consequences of altered OS-9 expression, neither knockdown nor overexpression of OS-9 was found to have a significant effect on CaSR cell surface expression or CaSR-mediated ERK1/2 phosphorylation. |
| first_indexed | 2025-11-14T09:57:18Z |
| format | Journal Article |
| id | curtin-20.500.11937-53988 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T09:57:18Z |
| publishDate | 2017 |
| publisher | John Wiley & Sons, Inc. |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-539882017-10-26T03:58:54Z The endoplasmic reticulum-associated protein, OS-9, behaves as a lectin in targeting the immature calcium-sensing receptor Ward, B. Rea, S. Magno, A. Pedersen, B. Brown, S. Mullin, S. Arulpragasam, Ajanthy Ingley, E. Conigrave, A. Ratajczak, T. The mechanisms responsible for the processing and quality control of the calcium-sensing receptor (CaSR) in the endoplasmic reticulum (ER) are largely unknown. In a yeast two-hybrid screen of the CaSR C-terminal tail (residues 865-1078), we identified osteosarcoma-9 (OS-9) protein as a binding partner. OS-9 is an ER-resident lectin that targets misfolded glycoproteins to the ER-associated degradation (ERAD) pathway through recognition of specific N-glycans by its mannose-6-phosphate receptor homology (MRH) domain. We show by confocal microscopy that the CaSR and OS-9 co-localize in the ER in COS-1 cells. In immunoprecipitation studies with co-expressed OS-9 and CaSR, OS-9 specifically bound the immature form of wild-type CaSR in the ER. OS-9 also bound the immature forms of a CaSR C-terminal deletion mutant and a C677A mutant that remains trapped in the ER, although binding to neither mutant was favored over wild-type receptor. OS-9 binding to immature CaSR required the MRH domain of OS-9 indicating that OS-9 acts as a lectin most likely to target misfolded CaSR to ERAD. Our results also identify two distinct binding interactions between OS-9 and the CaSR, one involving both C-terminal domains of the two proteins and the other involving both N-terminal domains. This suggests the possibility of more than one functional interaction between OS-9 and the CaSR. When we investigated the functional consequences of altered OS-9 expression, neither knockdown nor overexpression of OS-9 was found to have a significant effect on CaSR cell surface expression or CaSR-mediated ERK1/2 phosphorylation. 2017 Journal Article http://hdl.handle.net/20.500.11937/53988 10.1002/jcp.25957 John Wiley & Sons, Inc. unknown |
| spellingShingle | Ward, B. Rea, S. Magno, A. Pedersen, B. Brown, S. Mullin, S. Arulpragasam, Ajanthy Ingley, E. Conigrave, A. Ratajczak, T. The endoplasmic reticulum-associated protein, OS-9, behaves as a lectin in targeting the immature calcium-sensing receptor |
| title | The endoplasmic reticulum-associated protein, OS-9, behaves as a lectin in targeting the immature calcium-sensing receptor |
| title_full | The endoplasmic reticulum-associated protein, OS-9, behaves as a lectin in targeting the immature calcium-sensing receptor |
| title_fullStr | The endoplasmic reticulum-associated protein, OS-9, behaves as a lectin in targeting the immature calcium-sensing receptor |
| title_full_unstemmed | The endoplasmic reticulum-associated protein, OS-9, behaves as a lectin in targeting the immature calcium-sensing receptor |
| title_short | The endoplasmic reticulum-associated protein, OS-9, behaves as a lectin in targeting the immature calcium-sensing receptor |
| title_sort | endoplasmic reticulum-associated protein, os-9, behaves as a lectin in targeting the immature calcium-sensing receptor |
| url | http://hdl.handle.net/20.500.11937/53988 |