PMID- 19029296 OWN - NLM STAT- MEDLINE DCOM- 20090407 LR - 20211020 IS - 0021-9258 (Print) IS - 1083-351X (Electronic) IS - 0021-9258 (Linking) VI - 284 IP - 5 DP - 2009 Jan 30 TI - Small GTPase determinants for the Golgi processing and plasmalemmal expression of human ether-a-go-go related (hERG) K+ channels. PG - 2844-2853 LID - S0021-9258(19)81849-5 [pii] LID - 10.1074/jbc.M807289200 [doi] AB - The pro-arrhythmic Long QT syndrome (LQT) is linked to 10 different genes (LQT1-10). Approximately 40% of genotype-positive LQT patients have LQT2, which is characterized by mutations in the human ether-a-go-go related gene (hERG). hERG encodes the voltage-gated K(+) channel alpha-subunits that form the pore of the rapidly activating delayed rectifier K(+) current in the heart. The purpose of this study was to elucidate the mechanisms that regulate the intracellular transport or trafficking of hERG, because trafficking is impaired for about 90% of LQT2 missense mutations. Protein trafficking is regulated by small GTPases. To identify the small GTPases that are critical for hERG trafficking, we coexpressed hERG and dominant negative (DN) GTPase mutations in HEK293 cells. The GTPases Sar1 and ARF1 regulate the endoplasmic reticulum (ER) export of proteins in COPII and COPI vesicles, respectively. Expression of DN Sar1 inhibited the Golgi processing of hERG, decreased hERG current (I(hERG)) by 85% (n > or = 8 cells per group, *, p < 0.01), and reduced the plasmalemmal staining of hERG. The coexpression of DN ARF1 had relatively small effects on hERG trafficking. Surprisingly, the coexpression of DN Rab11B, which regulates the endosomal recycling, inhibited the Golgi processing of hERG, decreased I(hERG) by 79% (n > or = 8 cells per group; *, p < 0.01), and reduced the plasmalemmal staining of hERG. These data suggest that hERG undergoes ER export in COPII vesicles and endosomal recycling prior to being processed in the Golgi. We conclude that hERG trafficking involves a pathway between the ER and endosomal compartments that influences expression in the plasmalemma. FAU - Delisle, Brian P AU - Delisle BP AD - Department of Physiology, University of Kentucky, Lexington, Kentucky 40536. Electronic address: brian.delisle@uky.edu. FAU - Underkofler, Heather A S AU - Underkofler HAS AD - Cellular and Molecular Arrhythmia Research Program, Departments of Medicine and Physiology, University of Wisconsin, Madison, Wisconsin 53706. FAU - Moungey, Brooke M AU - Moungey BM AD - Cellular and Molecular Arrhythmia Research Program, Departments of Medicine and Physiology, University of Wisconsin, Madison, Wisconsin 53706. FAU - Slind, Jessica K AU - Slind JK AD - Cellular and Molecular Arrhythmia Research Program, Departments of Medicine and Physiology, University of Wisconsin, Madison, Wisconsin 53706. FAU - Kilby, Jennifer A AU - Kilby JA AD - Cellular and Molecular Arrhythmia Research Program, Departments of Medicine and Physiology, University of Wisconsin, Madison, Wisconsin 53706. FAU - Best, Jabe M AU - Best JM AD - Cellular and Molecular Arrhythmia Research Program, Departments of Medicine and Physiology, University of Wisconsin, Madison, Wisconsin 53706. FAU - Foell, Jason D AU - Foell JD AD - Cellular and Molecular Arrhythmia Research Program, Departments of Medicine and Physiology, University of Wisconsin, Madison, Wisconsin 53706. FAU - Balijepalli, Ravi C AU - Balijepalli RC AD - Cellular and Molecular Arrhythmia Research Program, Departments of Medicine and Physiology, University of Wisconsin, Madison, Wisconsin 53706. FAU - Kamp, Timothy J AU - Kamp TJ AD - Cellular and Molecular Arrhythmia Research Program, Departments of Medicine and Physiology, University of Wisconsin, Madison, Wisconsin 53706. FAU - January, Craig T AU - January CT AD - Cellular and Molecular Arrhythmia Research Program, Departments of Medicine and Physiology, University of Wisconsin, Madison, Wisconsin 53706. Electronic address: ctj@medicine.wisc.edu. LA - eng GR - R01 HL087039/HL/NHLBI NIH HHS/United States GR - R01 HL60723/HL/NHLBI NIH HHS/United States PT - Journal Article PT - Research Support, N.I.H., Extramural PT - Research Support, Non-U.S. Gov't DEP - 20081124 PL - United States TA - J Biol Chem JT - The Journal of biological chemistry JID - 2985121R RN - 0 (Ether-A-Go-Go Potassium Channels) RN - EC 3.6.1.- (GTP Phosphohydrolases) SB - IM MH - Cell Membrane/metabolism MH - Ether-A-Go-Go Potassium Channels/genetics/*metabolism MH - GTP Phosphohydrolases/*metabolism MH - Golgi Apparatus/*metabolism MH - Humans MH - Immunohistochemistry MH - Microscopy, Confocal MH - Mutagenesis, Site-Directed MH - Mutation, Missense MH - Patch-Clamp Techniques PMC - PMC2631954 EDAT- 2008/11/26 09:00 MHDA- 2009/04/08 09:00 PMCR- 2010/01/30 CRDT- 2008/11/26 09:00 PHST- 2008/11/26 09:00 [pubmed] PHST- 2009/04/08 09:00 [medline] PHST- 2008/11/26 09:00 [entrez] PHST- 2010/01/30 00:00 [pmc-release] AID - S0021-9258(19)81849-5 [pii] AID - 2844 [pii] AID - 10.1074/jbc.M807289200 [doi] PST - ppublish SO - J Biol Chem. 2009 Jan 30;284(5):2844-2853. doi: 10.1074/jbc.M807289200. Epub 2008 Nov 24.