Identification of SYWKQCAFNAVSCFamide: a broadly conserved crustacean C-type allatostatin-like peptide with both neuromodulatory and cardioactive properties

Abstract

SUMMARYThe allatostatins comprise three structurally distinct peptide families that regulate juvenile hormone production by the insect corpora allata. A-type family members contain the C-terminal motif -YXFGLamide and have been found in species from numerous arthropod taxa. Members of the B-type family exhibit a -WX 6 Wamide C-terminus and, like the A-type peptides, appear to be broadly conserved within the Arthropoda. By contrast, members of the C-type family, typified by the unblocked C-terminus -PISCF, a pyroglutamine blocked N-terminus, and a disulfide bridge between two internal Cys residues, have only been found in holometabolous insects, i.e. lepidopterans and dipterans. Here, using transcriptomics, we have identified SYWKQCAFNAVSCFamide (disulfide bridging predicted between the two Cys residues), a known honeybee and water flea C-typelike peptide, from the American lobster Homarus americanus (infraorder Astacidea). Using matrix assisted laser desorption/ionization Fourier transform mass spectrometry (MALDI-FTMS), a mass corresponding to that of SYWKQCAFNAVSCFamide was detected in the H. americanus brain, supporting the existence of this peptide and its theorized structure. Furthermore, SYWKQCAFNAVSCFamide was detected by MALDI-FTMS in neural tissues from five additional astacideans as well as 19 members of four other decapod infraorders (i.e. Achelata, Anomura, Brachyura and Thalassinidea), suggesting that it is a broadly conserved decapod peptide. In H. americanus, SYWKQCAFNAVSCFamide is capable of modulating the output of both the pyloric circuit of the stomatogastric nervous system and the heart. This is the first demonstration of bioactivity for this peptide in any species.

Identification of a calcitonin-like diuretic hormone that functions as an intrinsic modulator of the American lobster,Homarus americanus, cardiac neuromuscular system

“…Mercier and Russenes, 1992;Wilkens et al, 2005;Cruz-Bermúdez et al, 2006;Cruz-Bermúdez and Marder, 2007;Dickinson et al, 2007;Fort et al, 2007a;Fort et al, 2007b;Christie et al, 2008b;Dickinson et al, 2009). As described earlier, one H. americanus tissue in which CLDH message was detected is the CG, which controls the rhythmic beating of the heart.…”

“…In contrast, the finding of Homam-prepro-CLDH message in the CG was surprising; although the cardiac motor pattern is known to be extensively modulated by peptide hormones (e.g. Mercier and Russenes, 1992;Wilkens et al, 2005;Cruz-Bermúdez et al, 2006;Cruz-Bermúdez and Marder, 2007;Dickinson et al, 2007;Fort et al, 2007a;Fort et al, 2007b;Christie et al, 2008b;Dickinson et al, 2009), no peptides have been identified within the ganglion itself. By dividing the CG into pacemaker neuron-and motor neuron-specific regions, we were able to localize the production of the CLDH transcript to the latter cell type.…”

“…Ma et al, 2008), and commissural ganglion (e.g. Stemmler et al, 2007;Dickinson et al, 2009;Stemmler et al, 2010), none have thus far been detected in the CG somata of H. americanus, or, for that matter, any crustacean species. As the organization of the lobster CG is such that the somata of the two types of neurons present in the ganglion, the pacemaker and the motor neurons, can be readily isolated from one another (Fig.3A), we conducted RT-PCR profiling on neuron-specific tissue pools (N3 independent runs for each neuron type) in an attempt to determine in greater detail A. E. Christie and others the origin of the Homam-prepro-CLDH message in the CG.…”

“…Nucleotide translation and peptide prediction were conducted using a previously established protocol (Christie, 2008a;Christie, 2008b;Christie et al, 2008a;Gard et al, 2009;Dickinson et al, 2009;Ma et al, 2009;Stemmler et al, 2010). Specifically, cDNA sequence translation was done using the Translate tool of ExPASy (Swiss Institute of Bioinformatics, Basel, Switzerland; http://www.expasy.ch/tools/dna.html).…”

Identification, tissue distribution and orexigenic activity of neuropeptide F (NPF) in penaeid shrimp

“…Christie, 2008a;Christie, 2008b;Christie et al, 2008;Dickinson et al, 2009;Gard et al, 2009;Ma et al, 2009a;Christie et al, 2010b;Christie et al, 2010c;Ma et al, 2010;Stemmler et al, 2010). Specifically, nucleotide sequences were translated using the Translate tool of ExPASy [Swiss Institute of Bioinformatics, Basel, Switzerland; http://www.expasy.ch/tools/dna.html (Gasteiger et al, 2003)].…”