title: The Caenorhabditis elegans unc-13 gene product is a phospholipid-dependent high-affinity phorbol ester receptor.
abstract: The Caenorhabditis elegans unc-13 mutant is a member of a class of mutants that have un-coordinated movement. Mutations of the unc-13 gene cause diverse defects in C. elegans, including abnormal neuronal connections and modified synaptic transmission in the nervous system. unc-13 cDNA encodes a protein (UNC-13) of 1734 amino acid residues with a predicted molecular mass of 198 kDa and sequence identity to the C1/C2 regions but not to the catalytic domain of the ubiquitously expressed protein kinase C family [Maruyama & Brenner (1991) Proc. Natl. Acad. Sci. U.S.A. 88, 5729-5733]. To characterize the phorbol ester binding site of the UNC-13 protein, cDNA encoding the C1/C2-like regions (amino acid residues 546-940) was expressed in Escherichia coli and the 43 kDa recombinant protein was purified. Phorbol ester binding to the 43 kDa protein was zinc- and phospholipid-dependent, stereospecific and of high affinity (Kd 67 nM). UNC-13 specific antisera detected a protein of approx. 190 kDa in wild-type (N2) but not in mutant (e1019) C. elegans cell extracts. We conclude that UNC-13 represents a novel class of phorbol ester receptor.
authors.affiliation: Institute of Molecular and Cell Biology, National University of Singapore.
authors.forename: S
authors.initials: S
authors.lastname: Ahmed
authors.forename: I N
authors.initials: IN
authors.lastname: Maruyama
authors.forename: R
authors.initials: R
authors.lastname: Kozma
authors.forename: J
authors.initials: J
authors.lastname: Lee
authors.forename: S
authors.initials: S
authors.lastname: Brenner
authors.forename: L
authors.initials: L
authors.lastname: Lim
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites / Q000235:genetics; D017173:Caenorhabditis elegans / Q000235:genetics* / Q000378:metabolism; D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins; D003001:Cloning, Molecular; D016384:Consensus Sequence; D004926:Escherichia coli; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000235:genetics; D010703:Phorbol Esters / Q000378:metabolism*; D010743:Phospholipids / Q000378:metabolism*; D011493:Protein Kinase C; D011955:Receptors, Drug / Q000235:genetics* / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D015032:Zinc / Q000378:metabolism
chemical_list: D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins; D010446:Peptide Fragments; D010703:Phorbol Esters; D010743:Phospholipids; D011955:Receptors, Drug; C083141:phorbol ester binding protein; C027776:phorbol ester receptor; D011493:Protein Kinase C; D015032:Zinc