The first sulfakinins (leucosulfakinin-I and II) were isolated from the cockroach Leucophaea maderae and assayed for its myotropic action on the cockroach hindgut (Nachman et al, 1986). The name is derived from the similarity to the mammalian peptide cholecystokinin and its sulfated tyrosine residue. This was the first sequenced insect peptide that was found to be homologous to a vertebrate peptide. The sulfakinins are characterized by a YGHMRFamide C-terminus, where the Y is commonly sulfated. A Drosophila gene encoding two sulfakinins (drosulfakinin-1 and 2; DSK-1 and 2) was cloned in 1988 (Nichols et al, 1988) and two Drosophila sulfakinin receptors (CG6857 and CG6881) have been identified with prominent similarities to mammalian CCK receptors (Kubiak et al 2002).
Only four pairs of sulfakinin immunoreactive neurons were revealed in the entire larval CNS of Drosophila and a small number of additional ones were found in the adult brain, including the insulin-producing median neurosecretory cells (Nichols and Lim, 1996; Söderberg et al, 2012). Also in other insects sulfakinins are present in a few neurons of the brain (Duve et al, 1995; East et al, 1997).
In Drosophila, as well as in several other insect species sulfakinins have been shown to inhibit feeding (Söderberg et al, 2012; Yu et al, 2013; Zels et al, 2015) and in locusts the peptide additionally displays effects on digestive enzyme secretion in the gut (Zels et al 2015). In Drosophila, increased DSK signaling induces hyperactivity and aggression (Williams et al, 2014).
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- Yu N, Smagghe G. 2014. CCK(-like) and receptors: Structure and phylogeny in a comparative perspective. Gen Comp Endocrinol. 209:74-81.
Nässel DR, Williams MJ. 2014. Cholecystokinin-Like Peptide (DSK) in Drosophila, Not Only for Satiety Signaling. Front Endocrinol 5:219.
- Duve H, Thorpe A, Scott AG, Johnsen AH, Rehfeld JF, Hines E, East PD. 1995. The sulfakinins of the blowfly Calliphora vomitoria. Peptide isolation, gene cloning and expression studies. Eur J Biochem 232(2):633-640.
East PD, Hales DF, Cooper PD. 1997. Distribution of sulfakinin-like peptides in the central and sympathetic nervous system of the American cockroach, Periplaneta Americana (L.) and the field cricket, Teleogryllus commodus (Walker). Tissue & cell 29(3):347-354.
Kubiak TM, Larsen MJ, Burton KJ, Bannow CA, Martin RA, Zantello MR, Lowery DE. 2002. Cloning and functional expression of the first Drosophila melanogaster sulfakinin receptor DSK-R1. Biochem Biophys Res Commun 291(2):313-320.
Nachman RJ, Holman GM, Haddon WF, Ling N. 1986. Leucosulfakinin, a sulfated insect neuropeptide with homology to gastrin and cholecystokinin. Science 234(4772):71-73.
Nichols R, Schneuwly SA, Dixon JE. 1988. Identification and characterization of a Drosophila homologue to the vertebrate neuropeptide cholecystokinin. J Biol Chem 263(25):12167-12170.
Nichols R, Lim IA. 1996. Spatial and temporal immunocytochemical analysis of drosulfakinin (Dsk) gene products in the Drosophila melanogaster central nervous system. Cell Tissue Res 283(1):107-116.
Söderberg JA, Carlsson MA, Nässel DR. 2012. Insulin-Producing Cells in the Drosophila Brain also Express Satiety-Inducing Cholecystokinin-Like Peptide, Drosulfakinin. Front Endocrinol 3:109.
Williams MJ, Goergen P, Rajendran J, Klockars A, Kasagiannis A, Fredriksson R, Schioth HB. 2014. Regulation of aggression by obesity-linked genes TfAP-2 and Twz through octopamine signaling in Drosophila. Genetics 196(1):349-362.
Zels S, Dillen S, Crabbe K, Spit J, Nachman RJ, Vanden Broeck J. 2015. Sulfakinin is an important regulator of digestive processes in the migratory locust, Locusta migratoria. Insect Biochem Mol Biol 61:8-16.
Yu N, Nachman RJ, Smagghe G. 2013. Characterization of sulfakinin and sulfakinin receptor and their roles in food intake in the red flour beetle Tribolium castaneum. Gen Comp Endocrinol 188:196-203.