title: UNC-5 function requires phosphorylation of cytoplasmic tyrosine 482, but its UNC-40-independent functions also require a region between the ZU-5 and death domains.
abstract: Members of the UNC-5 protein family are transmembrane receptors for UNC-6/netrin guidance cues. To analyze the functional roles of different UNC-5 domains, we sequenced mutations in seven severe and three weak alleles of unc-5 in Caenorhabditis elegans. Four severe alleles contain nonsense mutations. Two weak alleles are truncations of the cytodomain, but one is a missense mutation in an extracellular immunoglobulin domain. To survey the function of different regions of UNC-5, wild-type and mutant unc-5::HA transgenes were tested for their ability to rescue the unc-5(e53) null mutant. Our data reveal partial functional requirements for the extracellular domains and identify a portion of the cytoplasmic juxtamembrane (JM) region as essential for rescue of migrations. When nine cytodomain tyrosines, including seven in the JM region, are mutated to phenylalanine, UNC-5 function and tyrosine phosphorylation are largely compromised. When F482 in the JM region of the mutant protein is reverted to tyrosine, UNC-5 tyrosine phosphorylation and in vivo function are largely recovered, suggesting that Y482 phosphorylation is critical to UNC-5 function in vivo. Our data also show that part of the ZU-5 motif is required for UNC-40-independent signaling of UNC-5.
authors.affiliation: Samuel Lunenfeld Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, Ontario M5G 1X5, Canada.
authors.forename: Marie
authors.initials: M
authors.lastname: Killeen
authors.forename: Jeifei
authors.initials: J
authors.lastname: Tong
authors.forename: Aldis
authors.initials: A
authors.lastname: Krizus
authors.forename: Robert
authors.initials: R
authors.lastname: Steven
authors.forename: Ian
authors.initials: I
authors.lastname: Scott
authors.forename: Tony
authors.initials: T
authors.lastname: Pawson
authors.forename: Joseph
authors.initials: J
authors.lastname: Culotti
mesh_terms: D000818:Animals; D029742:Caenorhabditis elegans Proteins / Q000032:analysis / Q000737:chemistry / Q000502:physiology*; D015815:Cell Adhesion Molecules / Q000502:physiology*; D002465:Cell Movement; D003593:Cytoplasm / Q000737:chemistry; D010766:Phosphorylation; D011956:Receptors, Cell Surface / Q000032:analysis / Q000737:chemistry / Q000502:physiology*; D013329:Structure-Activity Relationship; D014443:Tyrosine / Q000378:metabolism
chemical_list: D029742:Caenorhabditis elegans Proteins; D015815:Cell Adhesion Molecules; D011956:Receptors, Cell Surface; C102174:UNC-40 protein, C elegans; C077588:UNC-5 protein, C elegans; D014443:Tyrosine