A cryptic non-GPI-anchored cytosolic isoform of CD59 controls insulin exocytosis in pancreatic β-cells by interaction with SNARE proteins
(2019) In FASEB journal : official publication of the Federation of American Societies for Experimental Biology 33(11). p.12425-12434- Abstract
CD59 is a glycosylphosphatidylinositol (GPI)-anchored cell surface inhibitor of the complement membrane attack complex (MAC). We showed previously that CD59 is highly expressed in pancreatic islets but is down-regulated in rodent models of diabetes. CD59 knockdown but not enzymatic removal of cell surface CD59 led to a loss of glucose-stimulated insulin secretion (GSIS), suggesting that an intracellular pool of CD59 is required. In this current paper, we now report that non-GPI-anchored CD59 is present in the cytoplasm, colocalizes with exocytotic protein vesicle-associated membrane protein 2, and completely rescues GSIS in cells lacking endogenous CD59 expression. The involvement of cytosolic non-GPI-anchored CD59 in GSIS is supported... (More)
CD59 is a glycosylphosphatidylinositol (GPI)-anchored cell surface inhibitor of the complement membrane attack complex (MAC). We showed previously that CD59 is highly expressed in pancreatic islets but is down-regulated in rodent models of diabetes. CD59 knockdown but not enzymatic removal of cell surface CD59 led to a loss of glucose-stimulated insulin secretion (GSIS), suggesting that an intracellular pool of CD59 is required. In this current paper, we now report that non-GPI-anchored CD59 is present in the cytoplasm, colocalizes with exocytotic protein vesicle-associated membrane protein 2, and completely rescues GSIS in cells lacking endogenous CD59 expression. The involvement of cytosolic non-GPI-anchored CD59 in GSIS is supported in phosphatidylinositol glycan class A knockout GPI anchor-deficient β-cells, in which GSIS is still CD59 dependent. Furthermore, site-directed mutagenesis demonstrated different structural requirements of CD59 for its 2 functions, MAC inhibition and GSIS. Our results suggest that CD59 is retrotranslocated from the endoplasmic reticulum to the cytosol, a process mediated by recognition of trimmed N-linked oligosaccharides, supported by the partial glycosylation of non-GPI-anchored cytosolic CD59 as well as the failure of N-linked glycosylation site mutant CD59 to reach the cytosol or rescue GSIS. This study thus proposes the previously undescribed existence of non-GPI-anchored cytosolic CD59, which is required for insulin secretion.-Golec, E., Rosberg, R., Zhang, E., Renström, E., Blom, A. M., King, B. C. A cryptic non-GPI-anchored cytosolic isoform of CD59 controls insulin exocytosis in pancreatic β-cells by interaction with SNARE proteins.
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- author
- Golec, Ewelina LU ; Rosberg, Rebecca LU ; Zhang, Enming LU ; Renström, Erik LU ; Blom, Anna M LU and King, Ben C LU
- organization
-
- EXODIAB: Excellence of Diabetes Research in Sweden
- Protein Chemistry, Malmö (research group)
- Brain Tumor Biology (research group)
- Division of Translational Cancer Research
- NanoLund: Centre for Nanoscience
- Diabetes - Islet Patophysiology (research group)
- BioCARE: Biomarkers in Cancer Medicine improving Health Care, Education and Innovation
- publishing date
- 2019-11
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Animals, CD59 Antigens/genetics, CHO Cells, Cricetulus, Cytosol/metabolism, Exocytosis, Insulin/genetics, Insulin Secretion, Insulin-Secreting Cells/cytology, Oligosaccharides/genetics, Rats, SNARE Proteins/genetics
- in
- FASEB journal : official publication of the Federation of American Societies for Experimental Biology
- volume
- 33
- issue
- 11
- pages
- 10 pages
- publisher
- Wiley
- external identifiers
-
- scopus:85074377944
- pmid:31412214
- ISSN
- 1530-6860
- DOI
- 10.1096/fj.201901007R
- language
- English
- LU publication?
- yes
- id
- 86917bb5-a6bd-48fb-bb00-5268b4ae6eff
- date added to LUP
- 2021-03-09 21:57:58
- date last changed
- 2024-07-26 13:54:47
@article{86917bb5-a6bd-48fb-bb00-5268b4ae6eff, abstract = {{<p>CD59 is a glycosylphosphatidylinositol (GPI)-anchored cell surface inhibitor of the complement membrane attack complex (MAC). We showed previously that CD59 is highly expressed in pancreatic islets but is down-regulated in rodent models of diabetes. CD59 knockdown but not enzymatic removal of cell surface CD59 led to a loss of glucose-stimulated insulin secretion (GSIS), suggesting that an intracellular pool of CD59 is required. In this current paper, we now report that non-GPI-anchored CD59 is present in the cytoplasm, colocalizes with exocytotic protein vesicle-associated membrane protein 2, and completely rescues GSIS in cells lacking endogenous CD59 expression. The involvement of cytosolic non-GPI-anchored CD59 in GSIS is supported in phosphatidylinositol glycan class A knockout GPI anchor-deficient β-cells, in which GSIS is still CD59 dependent. Furthermore, site-directed mutagenesis demonstrated different structural requirements of CD59 for its 2 functions, MAC inhibition and GSIS. Our results suggest that CD59 is retrotranslocated from the endoplasmic reticulum to the cytosol, a process mediated by recognition of trimmed N-linked oligosaccharides, supported by the partial glycosylation of non-GPI-anchored cytosolic CD59 as well as the failure of N-linked glycosylation site mutant CD59 to reach the cytosol or rescue GSIS. This study thus proposes the previously undescribed existence of non-GPI-anchored cytosolic CD59, which is required for insulin secretion.-Golec, E., Rosberg, R., Zhang, E., Renström, E., Blom, A. M., King, B. C. A cryptic non-GPI-anchored cytosolic isoform of CD59 controls insulin exocytosis in pancreatic β-cells by interaction with SNARE proteins.</p>}}, author = {{Golec, Ewelina and Rosberg, Rebecca and Zhang, Enming and Renström, Erik and Blom, Anna M and King, Ben C}}, issn = {{1530-6860}}, keywords = {{Animals; CD59 Antigens/genetics; CHO Cells; Cricetulus; Cytosol/metabolism; Exocytosis; Insulin/genetics; Insulin Secretion; Insulin-Secreting Cells/cytology; Oligosaccharides/genetics; Rats; SNARE Proteins/genetics}}, language = {{eng}}, number = {{11}}, pages = {{12425--12434}}, publisher = {{Wiley}}, series = {{FASEB journal : official publication of the Federation of American Societies for Experimental Biology}}, title = {{A cryptic non-GPI-anchored cytosolic isoform of CD59 controls insulin exocytosis in pancreatic β-cells by interaction with SNARE proteins}}, url = {{http://dx.doi.org/10.1096/fj.201901007R}}, doi = {{10.1096/fj.201901007R}}, volume = {{33}}, year = {{2019}}, }