Skip to main content
NCBI home page
Biochemical Journal logoLink to Biochemical Journal
. 2004 Jan 1;377(Pt 1):131–139. doi: 10.1042/BJ20031183

Structure-function analysis of HKE4, a member of the new LIV-1 subfamily of zinc transporters.

Kathryn M Taylor 1, Helen E Morgan 1, Andrea Johnson 1, Robert I Nicholson 1
PMCID: PMC1223853  PMID: 14525538

Abstract

The KE4 proteins are an emerging group of proteins with little known functional data. In the present study, we report the first characterization of the recombinant human KE4 protein in mammalian cells. The KE4 sequences are included in the subfamily of ZIP (Zrt-, Irt-like Proteins) zinc transporters, which we have termed LZT (LIV-1 subfamily of ZIP zinc Transporters). All these LZT sequences contain similarities to ZIP transporters, including the consensus sequence in transmembrane domain IV, which is essential for zinc transport. However, the new LZT subfamily can be separated from other ZIP transporters by the presence of a highly conserved potential metalloprotease motif (HEXPHEXGD) in transmembrane domain V. Here we report the location of HKE4 on intracellular membranes, including the endoplasmic reticulum, and its ability to increase the intracellular free zinc as measured with the zinc-specific fluorescent dye, Newport Green, in a time-, temperature- and concentration-dependent manner. This is in contrast with the zinc influx ability of another LZT protein, LIV-1, which was due to its plasma membrane location. Therefore we have added to the functionality of LZT proteins by reporting their ability to increase intracellular-free zinc, whether they are located on the plasma membrane or on intracellular membranes. This result, in combination with the crucial role that zinc plays in cell growth, emphasizes the importance of this new LZT subfamily, including the KE4 sequences, in the control of intracellular zinc homoeostasis, aberrations of which can lead to diseases such as cancer, immunological disorders and neurological dysfunction.

Full Text

The Full Text of this article is available as a PDF (425.3 KB).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Ando A., Kikuti Y. Y., Shigenari A., Kawata H., Okamoto N., Shiina T., Chen L., Ikemura T., Abe K., Kimura M. cDNA cloning of the human homologues of the mouse Ke4 and Ke6 genes at the centromeric end of the human MHC region. Genomics. 1996 Aug 1;35(3):600–602. doi: 10.1006/geno.1996.0405. [DOI] [PubMed] [Google Scholar]
  2. Begum Nasim A., Kobayashi Mika, Moriwaki Yasuhiro, Matsumoto Misako, Toyoshima Kumao, Seya Tsukasa. Mycobacterium bovis BCG cell wall and lipopolysaccharide induce a novel gene, BIGM103, encoding a 7-TM protein: identification of a new protein family having Zn-transporter and Zn-metalloprotease signatures. Genomics. 2002 Dec;80(6):630–645. doi: 10.1006/geno.2002.7000. [DOI] [PubMed] [Google Scholar]
  3. Brendel V., Bucher P., Nourbakhsh I. R., Blaisdell B. E., Karlin S. Methods and algorithms for statistical analysis of protein sequences. Proc Natl Acad Sci U S A. 1992 Mar 15;89(6):2002–2006. doi: 10.1073/pnas.89.6.2002. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Di Virgilio F., Steinberg T. H., Silverstein S. C. Inhibition of Fura-2 sequestration and secretion with organic anion transport blockers. Cell Calcium. 1990 Feb-Mar;11(2-3):57–62. doi: 10.1016/0143-4160(90)90059-4. [DOI] [PubMed] [Google Scholar]
  5. Gaither L. A., Eide D. J. Eukaryotic zinc transporters and their regulation. Biometals. 2001 Sep-Dec;14(3-4):251–270. doi: 10.1023/a:1012988914300. [DOI] [PubMed] [Google Scholar]
  6. Gaither L. A., Eide D. J. Functional expression of the human hZIP2 zinc transporter. J Biol Chem. 2000 Feb 25;275(8):5560–5564. doi: 10.1074/jbc.275.8.5560. [DOI] [PubMed] [Google Scholar]
  7. Gaither L. A., Eide D. J. The human ZIP1 transporter mediates zinc uptake in human K562 erythroleukemia cells. J Biol Chem. 2001 Apr 11;276(25):22258–22264. doi: 10.1074/jbc.M101772200. [DOI] [PubMed] [Google Scholar]
  8. Gitan R. S., Luo H., Rodgers J., Broderius M., Eide D. Zinc-induced inactivation of the yeast ZRT1 zinc transporter occurs through endocytosis and vacuolar degradation. J Biol Chem. 1998 Oct 30;273(44):28617–28624. doi: 10.1074/jbc.273.44.28617. [DOI] [PubMed] [Google Scholar]
  9. Hanson I. M., Trowsdale J. Colinearity of novel genes in the class II regions of the MHC in mouse and human. Immunogenetics. 1991;34(1):5–11. doi: 10.1007/BF00212306. [DOI] [PubMed] [Google Scholar]
  10. Hauri H., Appenzeller C., Kuhn F., Nufer O. Lectins and traffic in the secretory pathway. FEBS Lett. 2000 Jun 30;476(1-2):32–37. doi: 10.1016/s0014-5793(00)01665-3. [DOI] [PubMed] [Google Scholar]
  11. Janatipour M., Naumov Y., Ando A., Sugimura K., Okamoto N., Tsuji K., Abe K., Inoko H. Search for MHC-associated genes in human: five new genes centromeric to HLA-DP with yet unknown functions. Immunogenetics. 1992;35(4):272–278. doi: 10.1007/BF00166833. [DOI] [PubMed] [Google Scholar]
  12. Kendall J. M., Badminton M. N. Aequorea victoria bioluminescence moves into an exciting new era. Trends Biotechnol. 1998 May;16(5):216–224. doi: 10.1016/s0167-7799(98)01184-6. [DOI] [PubMed] [Google Scholar]
  13. Koh J. Y., Suh S. W., Gwag B. J., He Y. Y., Hsu C. Y., Choi D. W. The role of zinc in selective neuronal death after transient global cerebral ischemia. Science. 1996 May 17;272(5264):1013–1016. doi: 10.1126/science.272.5264.1013. [DOI] [PubMed] [Google Scholar]
  14. Lasswell J., Rogg L. E., Nelson D. C., Rongey C., Bartel B. Cloning and characterization of IAR1, a gene required for auxin conjugate sensitivity in Arabidopsis. Plant Cell. 2000 Dec;12(12):2395–2408. doi: 10.1105/tpc.12.12.2395. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Ma Dzwokai, Jan Lily Yeh. ER transport signals and trafficking of potassium channels and receptors. Curr Opin Neurobiol. 2002 Jun;12(3):287–292. doi: 10.1016/s0959-4388(02)00319-7. [DOI] [PubMed] [Google Scholar]
  16. Manning D. L., McClelland R. A., Knowlden J. M., Bryant S., Gee J. M., Green C. D., Robertson J. F., Blamey R. W., Sutherland R. L., Ormandy C. J. Differential expression of oestrogen regulated genes in breast cancer. Acta Oncol. 1995;34(5):641–646. doi: 10.3109/02841869509094041. [DOI] [PubMed] [Google Scholar]
  17. Molloy S. S., Anderson E. D., Jean F., Thomas G. Bi-cycling the furin pathway: from TGN localization to pathogen activation and embryogenesis. Trends Cell Biol. 1999 Jan;9(1):28–35. doi: 10.1016/s0962-8924(98)01382-8. [DOI] [PubMed] [Google Scholar]
  18. Nagata T., Weiss E. H., Abe K., Kitagawa K., Ando A., Yara-Kikuti Y., Seldin M. F., Ozato K., Inoko H., Taketo M. Physical mapping of the retinoid X receptor B gene in mouse and human. Immunogenetics. 1995;41(2-3):83–90. doi: 10.1007/BF00182317. [DOI] [PubMed] [Google Scholar]
  19. Petris M. J., Mercer J. F., Culvenor J. G., Lockhart P., Gleeson P. A., Camakaris J. Ligand-regulated transport of the Menkes copper P-type ATPase efflux pump from the Golgi apparatus to the plasma membrane: a novel mechanism of regulated trafficking. EMBO J. 1996 Nov 15;15(22):6084–6095. [PMC free article] [PubMed] [Google Scholar]
  20. Seidah N. G., Chrétien M. Proprotein and prohormone convertases: a family of subtilases generating diverse bioactive polypeptides. Brain Res. 1999 Nov 27;848(1-2):45–62. doi: 10.1016/s0006-8993(99)01909-5. [DOI] [PubMed] [Google Scholar]
  21. Sensi S. L., Yin H. Z., Carriedo S. G., Rao S. S., Weiss J. H. Preferential Zn2+ influx through Ca2+-permeable AMPA/kainate channels triggers prolonged mitochondrial superoxide production. Proc Natl Acad Sci U S A. 1999 Mar 2;96(5):2414–2419. doi: 10.1073/pnas.96.5.2414. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Stathakis D. G., Burton D. Y., McIvor W. E., Krishnakumar S., Wright T. R., O'Donnell J. M. The catecholamines up (Catsup) protein of Drosophila melanogaster functions as a negative regulator of tyrosine hydroxylase activity. Genetics. 1999 Sep;153(1):361–382. doi: 10.1093/genetics/153.1.361. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Strausberg Robert L., Feingold Elise A., Grouse Lynette H., Derge Jeffery G., Klausner Richard D., Collins Francis S., Wagner Lukas, Shenmen Carolyn M., Schuler Gregory D., Altschul Stephen F. Generation and initial analysis of more than 15,000 full-length human and mouse cDNA sequences. Proc Natl Acad Sci U S A. 2002 Dec 11;99(26):16899–16903. doi: 10.1073/pnas.242603899. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Sugawara A., Uruno A., Nagata T., Taketo M. M., Takeuchi K., Ito S. Characterization of mouse retinoid X receptor (RXR)-beta gene promoter: negative regulation by tumor necrosis factor (TNF)-alpha. Endocrinology. 1998 Jun;139(6):3030–3033. doi: 10.1210/endo.139.6.6130. [DOI] [PubMed] [Google Scholar]
  25. Suzuki Akiko, Endo Takeshi. Ermelin, an endoplasmic reticulum transmembrane protein, contains the novel HELP domain conserved in eukaryotes. Gene. 2002 Feb 6;284(1-2):31–40. doi: 10.1016/s0378-1119(01)00885-x. [DOI] [PubMed] [Google Scholar]
  26. Taylor K. M. LIV-1 breast cancer protein belongs to new family of histidine-rich membrane proteins with potential to control intracellular Zn2+ homeostasis. IUBMB Life. 2000 Apr;49(4):249–253. doi: 10.1080/15216540050033087. [DOI] [PubMed] [Google Scholar]
  27. Taylor K. M., Trimby A. R., Campbell A. K. Mutation of recombinant complement component C9 reveals the significance of the N-terminal region for polymerization. Immunology. 1997 May;91(1):20–27. doi: 10.1046/j.1365-2567.1997.00225.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  28. Taylor Kathryn M., Morgan Helen E., Johnson Andrea, Hadley Lisa J., Nicholson Robert I. Structure-function analysis of LIV-1, the breast cancer-associated protein that belongs to a new subfamily of zinc transporters. Biochem J. 2003 Oct 1;375(Pt 1):51–59. doi: 10.1042/BJ20030478. [DOI] [PMC free article] [PubMed] [Google Scholar]
  29. Taylor Kathryn M., Nicholson Robert I. The LZT proteins; the LIV-1 subfamily of zinc transporters. Biochim Biophys Acta. 2003 Apr 1;1611(1-2):16–30. doi: 10.1016/s0005-2736(03)00048-8. [DOI] [PubMed] [Google Scholar]
  30. Thompson J. D., Higgins D. G., Gibson T. J. CLUSTAL W: improving the sensitivity of progressive multiple sequence alignment through sequence weighting, position-specific gap penalties and weight matrix choice. Nucleic Acids Res. 1994 Nov 11;22(22):4673–4680. doi: 10.1093/nar/22.22.4673. [DOI] [PMC free article] [PubMed] [Google Scholar]
  31. Truong-Tran A. Q., Carter J., Ruffin R. E., Zalewski P. D. The role of zinc in caspase activation and apoptotic cell death. Biometals. 2001 Sep-Dec;14(3-4):315–330. doi: 10.1023/a:1012993017026. [DOI] [PubMed] [Google Scholar]
  32. Vallee B. L., Auld D. S. Zinc coordination, function, and structure of zinc enzymes and other proteins. Biochemistry. 1990 Jun 19;29(24):5647–5659. doi: 10.1021/bi00476a001. [DOI] [PubMed] [Google Scholar]
  33. Vallee B. L., Falchuk K. H. The biochemical basis of zinc physiology. Physiol Rev. 1993 Jan;73(1):79–118. doi: 10.1152/physrev.1993.73.1.79. [DOI] [PubMed] [Google Scholar]
  34. Wang Kun, Zhou Bing, Kuo Yien-Ming, Zemansky Jason, Gitschier Jane. A novel member of a zinc transporter family is defective in acrodermatitis enteropathica. Am J Hum Genet. 2002 May 24;71(1):66–73. doi: 10.1086/341125. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Biochemical Journal are provided here courtesy of The Biochemical Society

RESOURCES