Journal of Biochemistry Advance Access originally published online on May 22, 2007
Journal of Biochemistry 2007 142(1):123-129; doi:10.1093/jb/mvm113
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© 2007 The Japanese Biochemical Society.
Both Mammalian PIG-M and PIG-X are Required for Growth of GPI14-Disrupted Yeast
1Department of Biological Sciences, Sun Moon University, A-San City, Korea; 2Department of Immunoregulation, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan; and 3Genomic Research Center for Enteropathogenic Bacteria and Department of Microbiology, Chonnam National University Medical School, Gwangju, Korea
*To whom correspondence should be addressed. Tel: +82-41-530-2275, E-mail: kimyu{at}sunmoon.ac.kr
Received March 29, 2007; Accepted May 7, 2007
| Abstract |
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GPI mannosyltransferase I (GPI-MT-I) transfers the first mannose to a GPI-anchor precursor, glucosamine-(acyl)phosphatidylinositol [GlcN-(acyl)PI]. Mammalian GPI-MT-I consists of two components, PIG-M and PIG-X, which are homologous to Gpi14p and Pbn1p in Saccharomyces cerevisiae, respectively. In the present study, we disrupted yeast GPI14 and analysed the phenotype of gpi14 yeast. The gpi14 haploid cells were inviable and accumulated GlcN-(acyl)PI. We cloned PIG-M homologues from human, Plasmodium falciparum (PfPIG-M) and Trypanosoma brucei (TbGPI14), and tested whether they could complement gpi14-disrupted yeast. None of them restored GPI-MT-I activity and cell growth in gpi14-disrupted yeast. However, gpi14-disrupted yeast cells with human PIG-M, but not with PfPIG-M or TbGPI14, grew slowly but significantly when they were supplemented with rat PIG-X. This suggests that the association of PIG-X and PIG-M for GPI-MT-I activity is not interchangeable between mammals and the other lower eukaryotes.
Key Words: GPI14, human PIG-M, mannose, rat PIG-X, Saccharomyces cerevisiae
Abbreviations: GPI, Glycosylphosphatidylinositol; GPI-MT-I, GPI-mannosyltransferase I; PfPIG-M, Plasmodium falciparum PIG-M; TbGPI14, Trypanosoma brucei GPI14; GlcN-(acyl)PI, glucosamine-(acyl)phosphatidylinositol