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Temperature-Sensitive Random Insulin Granule Diffusion is a Prerequisite for Recruiting Granules for Release.

Ivarsson, Rosita LU ; Obermüller, Stefanie LU ; Rutter, Guy A; Galvanovskis, Juris LU and Renström, Erik LU (2004) In Traffic: the International Journal of Intracellular Transport 5(10). p.750-762
Abstract
Glucose-evoked insulin secretion exhibits a biphasic time course and is associated with accelerated intracellular granule movement. We combined live confocal imaging of EGFP-labelled insulin granules with capacitance measurements of exocytosis in clonal INS-1 cells to explore the relation between distinct random and directed modes of insulin granule movement, as well as exocytotic capacity. Reducing the temperature from 34 °C to 24 °C caused a dramatic 81% drop in the frequency of directed events, but reduced directed velocities by a mere 25%. The much stronger temperature sensitivity of the frequency of directed events (estimated energy of activation ~ 135 kJ/mol) than that of the granule velocities (~ 22 kJ/mol) suggests that... (More)
Glucose-evoked insulin secretion exhibits a biphasic time course and is associated with accelerated intracellular granule movement. We combined live confocal imaging of EGFP-labelled insulin granules with capacitance measurements of exocytosis in clonal INS-1 cells to explore the relation between distinct random and directed modes of insulin granule movement, as well as exocytotic capacity. Reducing the temperature from 34 °C to 24 °C caused a dramatic 81% drop in the frequency of directed events, but reduced directed velocities by a mere 25%. The much stronger temperature sensitivity of the frequency of directed events (estimated energy of activation ~ 135 kJ/mol) than that of the granule velocities (~ 22 kJ/mol) suggests that cooling-induced suppression of insulin granule movement is attributable to factors other than reduced motor protein adenosine 5'-triphosphatase activity. Indeed, cooling suppresses random granule diffusion by ~ 50%. In the single cell, the number of directed events depends on the extent of granule diffusion. Finally, single-cell exocytosis exhibits a biphasic pattern corresponding to that observed in vivo, and only the component reflecting 2nd phase insulin secretion is affected by cooling. We conclude that random diffusive movement is a prerequisite for directed insulin granule transport and for the recruitment of insulin granules released during 2nd phase insulin secretion. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Traffic: the International Journal of Intracellular Transport
volume
5
issue
10
pages
750 - 762
publisher
Wiley-Blackwell
external identifiers
  • wos:000223748400003
  • pmid:15355511
  • scopus:4744371528
ISSN
1398-9219
DOI
10.1111/j.1600-0854.2004.00216.x
language
English
LU publication?
yes
id
31e5f1bd-a4e6-4a4d-9882-e8e6db59f82f (old id 127530)
date added to LUP
2007-07-13 14:23:38
date last changed
2017-09-17 04:56:35
@article{31e5f1bd-a4e6-4a4d-9882-e8e6db59f82f,
  abstract     = {Glucose-evoked insulin secretion exhibits a biphasic time course and is associated with accelerated intracellular granule movement. We combined live confocal imaging of EGFP-labelled insulin granules with capacitance measurements of exocytosis in clonal INS-1 cells to explore the relation between distinct random and directed modes of insulin granule movement, as well as exocytotic capacity. Reducing the temperature from 34 °C to 24 °C caused a dramatic 81% drop in the frequency of directed events, but reduced directed velocities by a mere 25%. The much stronger temperature sensitivity of the frequency of directed events (estimated energy of activation ~ 135 kJ/mol) than that of the granule velocities (~ 22 kJ/mol) suggests that cooling-induced suppression of insulin granule movement is attributable to factors other than reduced motor protein adenosine 5'-triphosphatase activity. Indeed, cooling suppresses random granule diffusion by ~ 50%. In the single cell, the number of directed events depends on the extent of granule diffusion. Finally, single-cell exocytosis exhibits a biphasic pattern corresponding to that observed in vivo, and only the component reflecting 2nd phase insulin secretion is affected by cooling. We conclude that random diffusive movement is a prerequisite for directed insulin granule transport and for the recruitment of insulin granules released during 2nd phase insulin secretion.},
  author       = {Ivarsson, Rosita and Obermüller, Stefanie and Rutter, Guy A and Galvanovskis, Juris and Renström, Erik},
  issn         = {1398-9219},
  language     = {eng},
  number       = {10},
  pages        = {750--762},
  publisher    = {Wiley-Blackwell},
  series       = {Traffic: the International Journal of Intracellular Transport},
  title        = {Temperature-Sensitive Random Insulin Granule Diffusion is a Prerequisite for Recruiting Granules for Release.},
  url          = {http://dx.doi.org/10.1111/j.1600-0854.2004.00216.x},
  volume       = {5},
  year         = {2004},
}