Invertebrate FMRFamide Related Peptides

Department of Biological Sciences, Southern Illinois University Edwardsville, Illinois Box 1651, Edwardsville, IL 62026-1651. .
Protein and Peptide Letters (Impact Factor: 1.07). 05/2012; 20(6). DOI: 10.2174/0929866511320060005
Source: PubMed


In 1977 the neuropeptide FMRFamide was isolated from the clam, Macrocallista nimbosa. Since then several hundred FMRFamide-related peptides (FaRPs) have been isolated from invertebrate animals. Precursors to the FaRPs likely arose in the cnidarians. With the transition to a bilateral body plan FaRPs became a fixture in the invertebrate phyla. They have come to play a critical role as neurotransmitters, neuromodulators, and neurohormones. FaRPs regulate a variety of body functions including, feeding, digestion, circulation, reproduction, movement. The evolution of the molecular form and function of these omnipresent peptides will be considered.

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    • "These neurons are known to 20-Schmidt-Rhaesa-Chap20.indb 204 13/08/15 12:08 PM OUP-FIRST UNCORRECTED PROOF, August 13, 2015 throughout the molluscs (loi and tublitz 1997, Wollesen et al. 2010)(Fig. 20.5.G, H, I) and beyond (Krajniak 2013, Orchard and lange 2013). Schaefer et al. (Schaefer et al. 1985) first cloned and sequenced the FMRFamide gene in Aplysia and showed that the precursor protein is not only cleaved into several copies of FMRFamide, but also into numerous other peptides , which generally end with RFamide at the c terminus, but are elongated at the n-terminus from the four amino acids of FMRFamide itself, or alternatively, from the related peptide, FlRFamide. "
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    ABSTRACT: In the three decades since the FMRFamide peptide was isolated from the mollusk Macrocallista nimbosa, structurally similar peptides sharing a C-terminal RFamide motif have been identified across the animal kingdom. FMRFamide-like peptides (FLPs) represent the largest known family of neuropeptides in invertebrates. In the phylum Nematoda, at least 32 flp-genes are classified, making the FLP system of nematodes unusually complex. The diversity of the nematode FLP complement is most extensively mapped in Caenorhabditis elegans, where over 70 FLPs have been predicted. FLPs have shown to be expressed in the majority of the 302 C. elegans neurons including interneurons, sensory neurons, and motor neurons. The vast expression of FLPs is reflected in the broad functional repertoire of nematode FLP signaling, including neuroendocrine and neuromodulatory effects on locomotory activity, reproduction, feeding, and behavior. In contrast to the many identified nematode FLPs, only few peptides have been assigned a receptor and there is the need to clarify the pathway components and working mechanisms of the FLP signaling network. Here, we review the diversity, distribution, and functions of FLPs in nematodes.
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    ABSTRACT: Background: Trichoplax adhaerens is the best-known member of the phylum Placozoa, one of the earliest-diverging metazoan phyla. It is a small disk-shaped animal that glides on surfaces in warm oceans to feed on algae. Prior anatomical studies of Trichoplax revealed that it has a simple three-layered organization with four somatic cell types. Results: We reinvestigate the cellular organization of Trichoplax using advanced freezing and microscopy techniques to identify localize and count cells. Six somatic cell types are deployed in stereotyped positions. A thick ventral plate, comprising the majority of the cells, includes ciliated epithelial cells, newly identified lipophil cells packed with large lipid granules, and gland cells. Lipophils project deep into the interior, where they alternate with regularly spaced fiber cells whose branches contact all other cell types, including cells of the dorsal and ventral epithelium. Crystal cells, each containing a birefringent crystal, are arrayed around the rim. Gland cells express several proteins typical of neurosecretory cells, and a subset of them, around the rim, also expresses an FMRFamide-like neuropeptide. Conclusions: Structural analysis of Trichoplax with significantly improved techniques provides an advance in understanding its cell types and their distributions. We find two previously undetected cell types, lipohil and crystal cells, and an organized body plan in which different cell types are arranged in distinct patterns. The composition of gland cells suggests that they are neurosecretory cells and could control locomotor and feeding behavior.
    Current Biology 06/2014; 24(14). DOI:10.1016/j.cub.2014.05.046 · 9.57 Impact Factor
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