PUBLICATION
The cone-specific calcium sensor guanylate cyclase activating protein 4 from the zebrafish retina
- Authors
- Behnen, P., Scholten, A., Rätscho, N., and Koch, K.W.
- ID
- ZDB-PUB-080915-3
- Date
- 2009
- Source
- Journal of biological inorganic chemistry : JBIC : a publication of the Society of Biological Inorganic Chemistry 14(1): 89-99 (Journal)
- Registered Authors
- Keywords
- Calcium signalling, Neuronal calcium sensor protein, Guanylate cyclase, Zebrafish, Cone vision
- MeSH Terms
-
- Amino Acid Sequence
- Animals
- Calcium/analysis
- Calcium/metabolism*
- Calcium Signaling
- Gene Expression Regulation/genetics
- Guanylate Cyclase-Activating Proteins/chemistry
- Guanylate Cyclase-Activating Proteins/genetics
- Guanylate Cyclase-Activating Proteins/metabolism*
- Hydrophobic and Hydrophilic Interactions
- Molecular Sequence Data
- Retina/metabolism*
- Zebrafish*
- Zebrafish Proteins/chemistry
- Zebrafish Proteins/genetics
- Zebrafish Proteins/metabolism*
- PubMed
- 18777180 Full text @ J. Biol. Inorg. Chem.
Citation
Behnen, P., Scholten, A., Rätscho, N., and Koch, K.W. (2009) The cone-specific calcium sensor guanylate cyclase activating protein 4 from the zebrafish retina. Journal of biological inorganic chemistry : JBIC : a publication of the Society of Biological Inorganic Chemistry. 14(1):89-99.
Abstract
Guanylate cyclase activating proteins (GCAPs) serve as neuronal Ca(2+)-sensor proteins in vertebrate rod and cone photoreceptor cells. Zebrafish express in their retina a variety of six different GCAPs, of which four are specific for cone cells. One isoform, zGCAP4, is mainly expressed in double cones and long single cones. We cloned the zGCAP4 gene, purified non-myristoylated and myristoylated forms of the protein after heterologous expression in Escherichia coli and studied its properties: zGCAP4 was a strong activator of membrane-bound guanylate cyclases from bovine and zebrafish retina, showing half-maximal activation at 520-570 nM free Ca(2+) concentration. Furthermore, the Ca(2+)-sensitive activation properties of non-myristoylated and myristoylated zGCAP4 were similar, indicating no influence of the myristoyl moiety on Ca(2+)-sensor function. Myristoylated zGCAP4 showed low affinity for membranes and did not exhibit a Ca(2+)-myristoyl switch, a feature typical of some but not all neuronal Ca(2+)-sensor proteins. However, tryptophan fluorescence studies and Ca(2+)-dependent differences in protease accessibility revealed Ca(2+)-induced conformational changes in myristoylated and non-myristoylated zGCAP4, indicating the operation as a Ca(2+) sensor. Thus, expression and biochemical properties of zGCAP4 are in agreement with its function as an efficient Ca(2+)-sensitive regulator of guanylate cyclase activity in cone vision.
Genes / Markers
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Orthology
Engineered Foreign Genes
Mapping