title: SER-1, a Caenorhabditis elegans 5-HT2-like receptor, and a multi-PDZ domain containing protein (MPZ-1) interact in vulval muscle to facilitate serotonin-stimulated egg-laying.
abstract: Serotonin (5-HT) stimulation of egg-laying in Caenorhabditis elegans is abolished in ser-1 (ok345) animals and is rescued by ser-1 expression in vulval muscle. A PDZ binding motif (ETFL) at the SER-1 C-terminus is not essential for rescue, but facilitates SER-1 signaling. SER-1 binds specifically to PDZ domain 10 of the multi-PDZ domain protein, MPZ-1, based on GST pulldown and co-immunoprecipitation. mpz-1 is expressed in about 60 neurons and body wall and vulval muscles. In neurons, GFP-tagged MPZ-1 is punctate and colocalizes with the synaptic marker, synaptobrevin. The expression patterns of ser-1 and mpz-1 overlap in 3 pairs of neurons and vulval muscle. In addition, MPZ-1 also interacts with other GPCRs with acidic amino acids in the -3 position of their PDZ binding motifs. mpz-1 RNAi reduces 5-HT stimulated egg-laying in wild type animals and in ser-1 mutants rescued by muscle expression of SER-1. In contrast, mpz-1 RNAi has no effect on 5-HT stimulated egg-laying in ser-1 mutants rescued by expression of a truncated SER-1 that lacks the C-terminal PDZ binding motif. The overexpression of MPZ-1 PDZ domain 10 also inhibits 5-HT stimulated egg-laying. These studies suggest that the SER-1/MPZ-1 interaction facilitates SER-1 mediated signaling.
authors.affiliation: Department of Biological Sciences, University of Toledo, 2801 West Bancroft Street, Toledo, OH 43606, USA.
authors.forename: Hong
authors.initials: H
authors.lastname: Xiao
authors.forename: Vera M
authors.initials: VM
authors.lastname: Hapiak
authors.forename: Katherine A
authors.initials: KA
authors.lastname: Smith
authors.forename: Li
authors.initials: L
authors.lastname: Lin
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Hobson
authors.forename: John
authors.initials: J
authors.lastname: Plenefisch
authors.forename: Richard
authors.initials: R
authors.lastname: Komuniecki
mesh_terms: D000818:Animals; D001483:Base Sequence; D017173:Caenorhabditis elegans / Q000502:physiology*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D004531:Eggs; D005260:Female; D008969:Molecular Sequence Data; D009132:Muscles / Q000378:metabolism* / Q000502:physiology; D009474:Neurons / Q000378:metabolism; D017434:Protein Structure, Tertiary; D034622:RNA Interference; D043562:Receptors, G-Protein-Coupled; D044348:Receptors, Serotonin, 5-HT2 / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D012689:Sequence Homology, Nucleic Acid; D012701:Serotonin / Q000494:pharmacology*; D015398:Signal Transduction; D014844:Vulva / Q000378:metabolism / Q000502:physiology
chemical_list: D029742:Caenorhabditis elegans Proteins; D043562:Receptors, G-Protein-Coupled; D044348:Receptors, Serotonin, 5-HT2; C515315:SER-1 protein, C elegans; D012701:Serotonin