Binding of calcium ions and SNAP-25 to the hexa EF-hand protein secretagogin
Rogstam, Annika LU ; Linse, Sara LU ; Lindqvist, Anders LU ; James, Peter LU
; Wagner, Ludwig
and Berggård, Tord
LU
(2007)
In Biochemical Journal
401(Pt 1).
p.353-363
- Abstract
- Secretagogin is a hexa EF-hand protein, which has been identified as a novel potential tumour marker. In the present study, we show that secretagogin binds four Ca2+ ions (log K-1 = 7.1 +/- 0.4, log K-2 = 4.7 +/- 0.6, log K-3 = 3.6 +/- 0.7 and log K-4 = 4.6 +/- 0.6 in physiological salt buffers) with a [Ca2+](0.5) of approx. 25 mu M. The tertiary structure of secretagogin changes significantly upon Ca2+ binding, but not upon Mg2+ binding, and the amount of exposed hydrophobic surface in secretagogin increases upon Ca2+ binding, but not upon Mg2+ binding. These properties suggest that secretagogin belongs to the 'sensor' family of Ca2+-binding proteins. However, in contrast with the prototypical Ca2+ sensor calmodulin, which interacts with... (More)
- Secretagogin is a hexa EF-hand protein, which has been identified as a novel potential tumour marker. In the present study, we show that secretagogin binds four Ca2+ ions (log K-1 = 7.1 +/- 0.4, log K-2 = 4.7 +/- 0.6, log K-3 = 3.6 +/- 0.7 and log K-4 = 4.6 +/- 0.6 in physiological salt buffers) with a [Ca2+](0.5) of approx. 25 mu M. The tertiary structure of secretagogin changes significantly upon Ca2+ binding, but not upon Mg2+ binding, and the amount of exposed hydrophobic surface in secretagogin increases upon Ca2+ binding, but not upon Mg2+ binding. These properties suggest that secretagogin belongs to the 'sensor' family of Ca2+-binding proteins. However, in contrast with the prototypical Ca2+ sensor calmodulin, which interacts with a very large number of proteins, secretagogin is significantly less promiscuous. Only one secretagogin-interacting protein was reproducibly identified from insulinoma cell lysates and from bovine and mouse brain homogenates. This protein was identified as SNAP-25 (25 kDa synaptosome-associated protein), a protein involved in Ca2+-induced exocytosis in neurons and in neuroendocrine cells. K-d was determined to be 1.2 x 10(-7) M in the presence of Ca2+ and 1.5 x 10(-6) M in the absence of Ca2+. The comparatively low Ca2+ affinity for secretagogin and the fact that it undergoes Ca2+-induced conformational changes and interacts with SNAP-25 raise the possibility that secretagogin may link Ca2+ signalling to exocytotic processes. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/677565
- author
- Rogstam, Annika
LU
; Linse, Sara
LU
; Lindqvist, Anders
LU
; James, Peter
LU
; Wagner, Ludwig
and Berggård, Tord
LU
- organization
- publishing date
- 2007
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- secretagogin, conformational change, 25 kDa, sensor, calcium binding, synaptosome-associated protein (SNAP-25), EF-hand
- in
- Biochemical Journal
- volume
- 401
- issue
- Pt 1
- pages
- 353 - 363
- publisher
- Portland Press
- external identifiers
-
- wos:000243538800036
- scopus:33846299257
- ISSN
- 0264-6021
- DOI
- 10.1042/BJ20060918
- language
- English
- LU publication?
- yes
- additional info
- The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Department of Immunotechnology (011029300), Biophysical Chemistry (LTH) (011001011), Department of Cell and Organism Biology (Closed 2011.) (011002100), Islet cell physiology (013212142)
- id
- aeecb94a-20ac-411a-b3a1-81adb95f3736 (old id 677565)
- date added to LUP
- 2016-04-01 16:45:14
- date last changed
- 2023-11-14 17:10:29
@article{aeecb94a-20ac-411a-b3a1-81adb95f3736,
abstract = {{Secretagogin is a hexa EF-hand protein, which has been identified as a novel potential tumour marker. In the present study, we show that secretagogin binds four Ca2+ ions (log K-1 = 7.1 +/- 0.4, log K-2 = 4.7 +/- 0.6, log K-3 = 3.6 +/- 0.7 and log K-4 = 4.6 +/- 0.6 in physiological salt buffers) with a [Ca2+](0.5) of approx. 25 mu M. The tertiary structure of secretagogin changes significantly upon Ca2+ binding, but not upon Mg2+ binding, and the amount of exposed hydrophobic surface in secretagogin increases upon Ca2+ binding, but not upon Mg2+ binding. These properties suggest that secretagogin belongs to the 'sensor' family of Ca2+-binding proteins. However, in contrast with the prototypical Ca2+ sensor calmodulin, which interacts with a very large number of proteins, secretagogin is significantly less promiscuous. Only one secretagogin-interacting protein was reproducibly identified from insulinoma cell lysates and from bovine and mouse brain homogenates. This protein was identified as SNAP-25 (25 kDa synaptosome-associated protein), a protein involved in Ca2+-induced exocytosis in neurons and in neuroendocrine cells. K-d was determined to be 1.2 x 10(-7) M in the presence of Ca2+ and 1.5 x 10(-6) M in the absence of Ca2+. The comparatively low Ca2+ affinity for secretagogin and the fact that it undergoes Ca2+-induced conformational changes and interacts with SNAP-25 raise the possibility that secretagogin may link Ca2+ signalling to exocytotic processes.}},
author = {{Rogstam, Annika and Linse, Sara and Lindqvist, Anders and James, Peter and Wagner, Ludwig and Berggård, Tord}},
issn = {{0264-6021}},
keywords = {{secretagogin; conformational change; 25 kDa; sensor; calcium binding; synaptosome-associated protein (SNAP-25); EF-hand}},
language = {{eng}},
number = {{Pt 1}},
pages = {{353--363}},
publisher = {{Portland Press}},
series = {{Biochemical Journal}},
title = {{Binding of calcium ions and SNAP-25 to the hexa EF-hand protein secretagogin}},
url = {{http://dx.doi.org/10.1042/BJ20060918}},
doi = {{10.1042/BJ20060918}},
volume = {{401}},
year = {{2007}},
}