The cone-specific calcium sensor guanylate cyclase activating protein 4 from the zebrafish retina.
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.
Behnen
Petra
P
Biochemistry Group, Institute of Biology and Environmental Science, Faculty V, Carl von Ossietzky University Oldenburg, 26111, Oldenburg, Germany.
Scholten
Alexander
A
Rätscho
Nina
N
Koch
Karl-Wilhelm
KW
D000595:Amino Acid Sequence; D000818:Animals; D002118:Calcium / Q000032:analysis / Q000378:metabolism*; D020013:Calcium Signaling; D005786:Gene Expression Regulation / Q000235:genetics; D051604:Guanylate Cyclase-Activating Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D057927:Hydrophobic and Hydrophilic Interactions; D008969:Molecular Sequence Data; D012160:Retina / Q000378:metabolism*; D015027:Zebrafish; D029961:Zebrafish Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D051604:Guanylate Cyclase-Activating Proteins; D029961:Zebrafish Proteins; D002118:Calcium
Annu Rev Biochem. 1988;57:69-99
3052287
J Neurobiol. 2003 Jan;54(1):148-60
12486702
J Biol Chem. 1995 Oct 20;270(42):25200-6
7559656
J Mol Biol. 1982 May 5;157(1):105-32
7108955
J Neurosci. 2003 Jan 15;23(2):470-80
12533607
J Mol Evol. 2004 Aug;59(2):204-217
15486694
J Neurochem. 2007 Nov;103(4):1439-46
17868328
J Exp Biol. 2005 Apr;208(Pt 7):1337-45
15781894
Physiol Rev. 2001 Jan;81(1):117-151
11152756
Neuron. 1994 Aug;13(2):395-404
7520254
J Biol Chem. 2006 Aug 18;281(33):23830-41
16793776
J Biol Chem. 1999 Jul 2;274(27):19329-37
10383444
J Biol Chem. 1999 Mar 5;274(10):6526-35
10037746
J Comp Neurol. 1984 Mar 20;224(1):107-15
6715574
Eur J Biochem. 2003 Sep;270(18):3814-21
12950265
Nat Rev Neurosci. 2007 Mar;8(3):182-93
17311005
Anal Biochem. 1976 May 7;72:248-54
942051
Int J Dev Neurosci. 2001 Nov;19(7):621-9
11705666
J Biol Chem. 2002 Apr 19;277(16):14227-37
11836243
Proc Natl Acad Sci U S A. 1992 Dec 1;89(23):11569-73
1454850
Methods Enzymol. 2000;316:536-57
10800700
Neuron. 1996 Aug;17(2):323-31
8780655
Biochemistry. 2002 Oct 29;41(43):13021-8
12390029
Vis Neurosci. 2004 Jul-Aug;21(4):599-609
15579223
J Physiol. 2001 Apr 15;532(Pt 2):305-21
11306652
J Biol Chem. 1996 Apr 5;271(14):8022-7
8626484
Eur J Biochem. 2004 Sep;271(18):3785-93
15355355
J Physiol. 2002 Aug 1;542(Pt 3):829-41
12154182
Genetics. 2003 Feb;163(2):663-75
12618404
Eur J Neurosci. 2002 Jan;15(1):63-78
11860507
Biochim Biophys Acta. 2002 Nov 4;1600(1-2):111-7
12445466
J Physiol. 2002 Aug 1;542(Pt 3):843-54
12154183
J Gen Physiol. 1999 Feb;113(2):267-77
9925824