title: HEP-COP, a novel human gene whose product is highly homologous to the alpha-subunit of the yeast coatomer protein complex.
abstract: A 4333-bp novel human cDNA sequence designated HEP-COP was isolated from the Hep3B hepatocellular carcinoma cell line by the RACE technique. Within HEP-COP was identified an ORF of 3672 bp encoding a deduced 1224-amino-acid (aa) sequence which exhibited striking homology with the 1201-aa sequence of RET1P, the alpha-subunit of the coatomer complex (alpha-COP) in Saccharomyces cerevisiae which participates in membrane transport between the endoplasmic reticulum and Golgi apparatus. The aa homology was highest in their N-terminal regions which each contained six WD-40 repeat motifs [Van der Voorn and Ploegh, FEBS Lett. 307 (1992) 131-134], and both proteins were predicted to be hydrophilic with similar estimated molecular masses of 138 324 and 135 599 Da, respectively. Northern blot hybridization demonstrated that HEP-COP was expressed in a wide range of human adult and fetal tissues. RT-PCR analysis revealed no differential expression of HEP-COP in 14 human cancer cell lines, as compared with normal control cells. Considering the close similarities between HEP-COP and yeast alpha-COP, and the ubiquitous expression of HEP-COP implying an essential cellular role, it is likely that HEP-COP is the human homologue of alpha-COP.
authors.affiliation: Department of Microbiology, Faculty of Medicine, National University of Singapore.
authors.forename: V T
authors.initials: VT
authors.lastname: Chow
authors.forename: H H
authors.initials: HH
authors.lastname: Quek
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D015152:Blotting, Northern; D020756:Coatomer Protein; D018076:DNA, Complementary; D015894:Genome, Human; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics*; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012689:Sequence Homology, Nucleic Acid; D014407:Tumor Cells, Cultured; D015003:Yeasts / Q000235:genetics
chemical_list: D020756:Coatomer Protein; D018076:DNA, Complementary; D008565:Membrane Proteins