title: Golgi-specific DHHC zinc finger protein GODZ mediates membrane Ca2+ transport.
abstract: The Golgi-specific zinc finger protein GODZ (palmitoyl acyltransferase/DHHC-3) mediates the palmitoylation and post-translational modification of many protein substrates that regulate membrane-protein interactions. Here, we show that GODZ also mediates Ca(2+) transport in expressing Xenopus laevis oocytes. Two-electrode voltage-clamp, fluorescence, and (45)Ca(2+) isotopic uptake determinations demonstrated voltage- and concentration-dependent, saturable, and substrate-inhibitable Ca(2+) transport in oocytes expressing GODZ cRNA but not in oocytes injected with water alone. Moreover, we show that GODZ-mediated Ca(2+) transport is regulated by palmitoylation, as the palmitoyl acyltransferase inhibitor 2-bromopalmitate or alteration of the acyltransferase DHHC motif (GODZ-DHHS) diminished GODZ-mediated Ca(2+) transport by approximately 80%. The GODZ mutation V61R abolished Ca(2+) transport but did not affect palmitoyl acyltransferase activity. Coexpression of GODZ-V61R with GODZ-DHHS restored GODZ-DHHS-mediated Ca(2+) uptake to values observed with wild-type GODZ, excluding an endogenous effect of palmitoylation. Coexpression of an independent palmitoyl acyltransferase (HIP14) with the GODZ-DHHS mutant also rescued Ca(2+) transport. HIP14 did not mediate Ca(2+) transport when expressed alone. Immunocytochemistry studies showed that GODZ and HIP14 co-localized to the Golgi and the same post-Golgi vesicles, suggesting that heteropalmitoylation might play a physiological role in addition to a biochemical function. We conclude that GODZ encodes a Ca(2+) transport protein in addition to its ability to palmitoylate protein substrates.
authors: Department of Psychiatry, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada.
authors: Rochelle M
authors: RM
authors: Hines
authors: Rujun
authors: R
authors: Kang
authors: Angela
authors: A
authors: Goytain
authors: Gary A
authors: GA
authors: Quamme
mesh_terms: D000217:Acyltransferases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D020816:Amino Acid Motifs / Q000235:genetics / Q000502:physiology; D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D002118:Calcium / Q000378:metabolism*; D002522:Chlorocebus aethiops; D006056:Golgi Apparatus / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D018613:Microscopy, Confocal; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D009865:Oocytes; D021381:Protein Transport / Q000235:genetics / Q000502:physiology; D014981:Xenopus / Q000235:genetics / Q000378:metabolism
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C465718:GODZ protein, mouse; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D049452:Green Fluorescent Proteins; D000217:Acyltransferases; C473038:ZDHHC17 protein, human; D002118:Calcium