Antibody inhibition of synaptosomal protein of 25 kDa (SNAP-25) and syntaxin 1 reduces rapid exocytosis in insulin-secreting cells.
Vikman, Jenny LU ; Ma, Xiaosong LU ; Hockerman, Gregory H ; Rorsman, Patrik LU and Eliasson, Lena LU
(2006)
In Journal of Molecular Endocrinology
36(3).
p.503-515
- Abstract
- SNARE-proteins (soluble NSF-attachment protein receptor) are important for Ca2+-dependent exocytosis. We have used capacitance measurements and confocal imaging to dissect the role of synaptosomal protein of 25 kDa (SNAP-25) and syntaxin 1 in rapid exocytosis in insulin-secreting pancreatic ß-cells. Following immunoneutralization of syntaxin 1 and SNAP-25, exocytosis was strongly reduced and associated with a marked reduction in the size of the readily releasable pool (RRP) by 65% and 86% in the presence of the anti-SNAP-25 and anti-syntaxin 1 antibodies respectively. The size of the immediately releasable pool (IRP), a subset of RRP in close association with the voltage-dependent Ca2+-channels, was reduced to an equal extent. The... (More)
- SNARE-proteins (soluble NSF-attachment protein receptor) are important for Ca2+-dependent exocytosis. We have used capacitance measurements and confocal imaging to dissect the role of synaptosomal protein of 25 kDa (SNAP-25) and syntaxin 1 in rapid exocytosis in insulin-secreting pancreatic ß-cells. Following immunoneutralization of syntaxin 1 and SNAP-25, exocytosis was strongly reduced and associated with a marked reduction in the size of the readily releasable pool (RRP) by 65% and 86% in the presence of the anti-SNAP-25 and anti-syntaxin 1 antibodies respectively. The size of the immediately releasable pool (IRP), a subset of RRP in close association with the voltage-dependent Ca2+-channels, was reduced to an equal extent. The reduction in IRP correlated with slowed release kinetics and the time constant ({tau}) increased from a control value of 16 to 36 ms and 51 ms after inclusion of anti-SNAP-25 and anti-syntaxin 1 antibodies respectively in the pipette solution. We further show that SNAP-25 and syntaxin 1 aggregate in clusters along the plasma membrane. The size of these clusters was estimated to be ~300 nm and every ß-cell contained ~400 SNAP-25/syntaxin 1 clusters. Whereas the inhibitory action of the anti-syntaxin 1 antibody on exocytosis could be attributed almost entirely to suppression of the voltage-dependent Ca2+-current (–40%), the effect of the anti-SNAP-25 antibody was not mediated by decreased Ca2+-entry and is more likely due to a direct interference with the exocytotic machinery. Our data are consistent with the concept that both syntaxin 1 and SNAP-25 are required for rapid exocytosis in ß-cells. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/156586
- author
- Vikman, Jenny
LU
; Ma, Xiaosong
LU
; Hockerman, Gregory H
; Rorsman, Patrik
LU
and Eliasson, Lena
LU
- organization
- publishing date
- 2006
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Journal of Molecular Endocrinology
- volume
- 36
- issue
- 3
- pages
- 503 - 515
- publisher
- Society for Endocrinology
- external identifiers
-
- wos:000238316400009
- scopus:33745182916
- ISSN
- 1479-6813
- DOI
- 10.1677/jme.1.01978
- language
- English
- LU publication?
- yes
- id
- cc9381e6-31f0-4591-bc09-2acb7829c1f1 (old id 156586)
- date added to LUP
- 2016-04-01 16:59:51
- date last changed
- 2024-01-11 18:45:34
@article{cc9381e6-31f0-4591-bc09-2acb7829c1f1,
abstract = {{SNARE-proteins (soluble NSF-attachment protein receptor) are important for Ca2+-dependent exocytosis. We have used capacitance measurements and confocal imaging to dissect the role of synaptosomal protein of 25 kDa (SNAP-25) and syntaxin 1 in rapid exocytosis in insulin-secreting pancreatic ß-cells. Following immunoneutralization of syntaxin 1 and SNAP-25, exocytosis was strongly reduced and associated with a marked reduction in the size of the readily releasable pool (RRP) by 65% and 86% in the presence of the anti-SNAP-25 and anti-syntaxin 1 antibodies respectively. The size of the immediately releasable pool (IRP), a subset of RRP in close association with the voltage-dependent Ca2+-channels, was reduced to an equal extent. The reduction in IRP correlated with slowed release kinetics and the time constant ({tau}) increased from a control value of 16 to 36 ms and 51 ms after inclusion of anti-SNAP-25 and anti-syntaxin 1 antibodies respectively in the pipette solution. We further show that SNAP-25 and syntaxin 1 aggregate in clusters along the plasma membrane. The size of these clusters was estimated to be ~300 nm and every ß-cell contained ~400 SNAP-25/syntaxin 1 clusters. Whereas the inhibitory action of the anti-syntaxin 1 antibody on exocytosis could be attributed almost entirely to suppression of the voltage-dependent Ca2+-current (–40%), the effect of the anti-SNAP-25 antibody was not mediated by decreased Ca2+-entry and is more likely due to a direct interference with the exocytotic machinery. Our data are consistent with the concept that both syntaxin 1 and SNAP-25 are required for rapid exocytosis in ß-cells.}},
author = {{Vikman, Jenny and Ma, Xiaosong and Hockerman, Gregory H and Rorsman, Patrik and Eliasson, Lena}},
issn = {{1479-6813}},
language = {{eng}},
number = {{3}},
pages = {{503--515}},
publisher = {{Society for Endocrinology}},
series = {{Journal of Molecular Endocrinology}},
title = {{Antibody inhibition of synaptosomal protein of 25 kDa (SNAP-25) and syntaxin 1 reduces rapid exocytosis in insulin-secreting cells.}},
url = {{http://dx.doi.org/10.1677/jme.1.01978}},
doi = {{10.1677/jme.1.01978}},
volume = {{36}},
year = {{2006}},
}