Earticle

초록

영어

Protein O-mannosylation is an essential protein modification that is evolutionarily conserved from bacteria to humans, which is initiated by protein O-mannosyltransferases (Pmts). In the endoplasmic reticulum, Pmt proteins catalyze the transfer of mannose residue to Ser/The residues of secretory proteins. The whole genome information of the thermotolerant methylotrophic yeast Hansenula polymorpha reveals the presence of five PMT homologs, HpPMT1, HpPMT2, HpPMT4, HpPMT5 and HpPMT6. Here we characterized H. polymorpha PMT genes, particularly focusing on a PMT1 subfamily gene, HpPMT5, and a PMT2 subfamily gene, HpPMT6. The promoters of all H. polymorpha PMT genes contain an HpHAC1p binding site, in consistent with their induced expression under UPR condition.Although a single deletion of either HpPMT5 or HpPMT6 did not generate any significant defects, the Hppmt1pmt5 and Hppmt1pmt6 double mutants became more susceptible to cell wall disturbing reagents than the Hppmt1 single deletion mutant. Furthermore, the analysis of HpWsc1 and HpMid2, cell surface sensors of cell wall integrity signaling, and H. polymorpha chitinase, an endogenous O-modified glycoprotein, indicated significant decrease in O-mannosylation in the both Hppmt1pmt5 and Hppmt1pmt6 double mutants. All the fully functional epitope-tagged HpPmt proteins were shown to localize at the ER/Golgi membrane, except for the soluble localization of HpPmt6.The co-IP experiments revealed the complex formation between HpPmt1 and HpPmt2, but no interaction between HpPmt5 and HpPmt2 even in the absence of HpPmt1. Whereas, interestingly, phosphorylation of the mitogen-activated protein kinase Mpk1, which resulted in the stimulation of the cell wall integrity pathway, was markedly activated both in Hppmt1 and Hppmt1pmt5 mutant strains,but not in the Hppmt1pmt6 strain compared to wild type under normal condition. Altogether, these results indicate that HpPmt5 and HpPmt6 have redundant functions to significantly compensate the loss of HpPmt1 in protein O-mannosylation that affects cell growth, cell wall integrity, and stress resistance of H. polymorpha.

저자

• Hyunah Kim [ Lab. of Molecular Systems Biology, Department of Life Science, Chung-Ang University, Seoul, 155-756, Korea ]
• Hye Yun Moon [ Lab. of Molecular Systems Biology, Department of Life Science, Chung-Ang University, Seoul, 155-756, Korea ]
• Seon Ah Cheon [ Lab. of Molecular Systems Biology, Department of Life Science, Chung-Ang University, Seoul, 155-756, Korea ]
• Dong-jik Lee [ Lab. of Molecular Systems Biology, Department of Life Science, Chung-Ang University, Seoul, 155-756, Korea ]
• Hyun Ah Kang [ Lab. of Molecular Systems Biology, Department of Life Science, Chung-Ang University, Seoul, 155-756, Korea ]

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간행물

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• 간행물명

  한국당과학회 학술대회

• 간기

  연간

• 수록기간

  2006~2022

• 십진분류

  KDC 517 DDC 614