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

• Published in: Developmental biology Vol. 251; no. 2; pp. 348 - 366
• Main Authors: Killeen, Marie, Tong, Jeifei, Krizus, Aldis, Steven, Robert, Scott, Ian, Pawson, Tony, Culotti, Joseph
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 15.11.2002
• Subjects: Animals; C. elegans; Caenorhabditis elegans Proteins - analysis; Caenorhabditis elegans Proteins - chemistry; Caenorhabditis elegans Proteins - physiology; Cell Adhesion Molecules - physiology; cell migration; Cell Movement; Cytoplasm - chemistry; netrin receptor; Phosphorylation; pioneer axon guidance; Receptors, Cell Surface - analysis; Receptors, Cell Surface - chemistry; Receptors, Cell Surface - physiology; Structure-Activity Relationship; Tyrosine - metabolism; UNC-40/DCC; UNC-5; UNC-6/netrin; UNC-5; C. elegans; pioneer axon guidance; cell migration; netrin receptor; UNC-40/DCC; UNC-6/netrin
• ISSN: 0012-1606; 1095-564X
• DOI: 10.1006/dbio.2002.0825

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.