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Complement inhibitor CD55 governs the integrity of membrane rafts in pancreatic beta cells, but plays no role in insulin secretion.

Nagaraj, Vini LU ; King, Ben LU ; Storm, Petter LU ; Vikman, Petter LU ; Ottosson Laakso, Emilia LU ; Blom, Anna LU and Renström, Erik LU (2015) In Biochemical and Biophysical Research Communications 460(3). p.518-524
Abstract
CD55 is a glycosylphosphatidylinositol-anchored protein, which inhibits complement activation by acting on the complement C3 convertases. CD55 is widely localized in the cholesterol rich regions of the cell plasma membrane termed membrane rafts. CD55 is attached to these specialized regions via a GPI link on the outer leaflet of the plasma membrane. Membrane rafts anchor many important signaling proteins, which control several cellular functions within the cell. For example, we recently demonstrated that the membrane raft protein and complement inhibitor CD59 also controls insulin secretion by an intracellular mechanism. Therefore, we have in this study aimed at addressing the expression and function of CD55 in pancreatic beta cells. To... (More)
CD55 is a glycosylphosphatidylinositol-anchored protein, which inhibits complement activation by acting on the complement C3 convertases. CD55 is widely localized in the cholesterol rich regions of the cell plasma membrane termed membrane rafts. CD55 is attached to these specialized regions via a GPI link on the outer leaflet of the plasma membrane. Membrane rafts anchor many important signaling proteins, which control several cellular functions within the cell. For example, we recently demonstrated that the membrane raft protein and complement inhibitor CD59 also controls insulin secretion by an intracellular mechanism. Therefore, we have in this study aimed at addressing the expression and function of CD55 in pancreatic beta cells. To this end, we observe that CD55 is highly expressed in INS1 832/13 beta cells as well as human pancreatic islets. Diabetic human islets show a tendency for increased expression of CD55 when compared to the healthy controls. Importantly, silencing of CD55 in INS1 832/13 cells does not affect their insulin secretory capacity. On the other hand, silencing of CD55 diminished the intensity of membrane rafts as determined by Atto-SM staining. We hence conclude that CD55 expression is affected by glycemic status in human islets and plays a critical role in maintaining the conserved structure of rafts in pancreatic islets, which is similar to that of the related complement inhibitor CD59. However CD55 does not interfere with insulin secretion in beta cells, which is in sharp contrast to the action of the complement inhibitor CD59. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Biochemical and Biophysical Research Communications
volume
460
issue
3
pages
518 - 524
publisher
Elsevier
external identifiers
  • pmid:25797618
  • wos:000359885300005
  • scopus:84937758770
ISSN
1090-2104
DOI
10.1016/j.bbrc.2015.03.062
language
English
LU publication?
yes
id
b4b1a717-903f-40aa-b777-cf100f8d20b4 (old id 5257862)
alternative location
http://www.ncbi.nlm.nih.gov/pubmed/25797618?dopt=Abstract
date added to LUP
2015-04-05 13:49:30
date last changed
2017-04-09 03:26:12
@article{b4b1a717-903f-40aa-b777-cf100f8d20b4,
  abstract     = {CD55 is a glycosylphosphatidylinositol-anchored protein, which inhibits complement activation by acting on the complement C3 convertases. CD55 is widely localized in the cholesterol rich regions of the cell plasma membrane termed membrane rafts. CD55 is attached to these specialized regions via a GPI link on the outer leaflet of the plasma membrane. Membrane rafts anchor many important signaling proteins, which control several cellular functions within the cell. For example, we recently demonstrated that the membrane raft protein and complement inhibitor CD59 also controls insulin secretion by an intracellular mechanism. Therefore, we have in this study aimed at addressing the expression and function of CD55 in pancreatic beta cells. To this end, we observe that CD55 is highly expressed in INS1 832/13 beta cells as well as human pancreatic islets. Diabetic human islets show a tendency for increased expression of CD55 when compared to the healthy controls. Importantly, silencing of CD55 in INS1 832/13 cells does not affect their insulin secretory capacity. On the other hand, silencing of CD55 diminished the intensity of membrane rafts as determined by Atto-SM staining. We hence conclude that CD55 expression is affected by glycemic status in human islets and plays a critical role in maintaining the conserved structure of rafts in pancreatic islets, which is similar to that of the related complement inhibitor CD59. However CD55 does not interfere with insulin secretion in beta cells, which is in sharp contrast to the action of the complement inhibitor CD59.},
  author       = {Nagaraj, Vini and King, Ben and Storm, Petter and Vikman, Petter and Ottosson Laakso, Emilia and Blom, Anna and Renström, Erik},
  issn         = {1090-2104},
  language     = {eng},
  number       = {3},
  pages        = {518--524},
  publisher    = {Elsevier},
  series       = {Biochemical and Biophysical Research Communications},
  title        = {Complement inhibitor CD55 governs the integrity of membrane rafts in pancreatic beta cells, but plays no role in insulin secretion.},
  url          = {http://dx.doi.org/10.1016/j.bbrc.2015.03.062},
  volume       = {460},
  year         = {2015},
}