| Title |
Prediction of Bacterial Proteins Carrying A Nuclear Localization Signal and Nuclear Targeting of HsdM from Klebsiella pneumoniae |
| Author |
Je Chul Lee1, Dong Sun Kim2, Dong Chan Moon1, Jung-Hwa Lee1, Mi Jin Kim2, Su Man Lee2, Yong Seok Lee3, Se-Won Kang3, Eun Jung Lee4, Sang Sun Kang5, Eunpyo Lee6, and Sung Hee Hyun4* |
| Address |
1Department of Microbiology, Kyungpook National University School of Medicine, Daegu 702-701, Republic of Korea, 2Anatomy, Kyungpook National University School of Medicine, Daegu 702-701, Republic of Korea, 3Department of Parasitology, College of Medicine and Frontier Inje Research for Science and Technology, Inje University, Busan 614-735, Republic of Korea, 4Department of Biomedical Laboratory Science, Eulji University, School of Medicine, Daejeon 301-746, Republic of Korea, 5School of Science Education, Chungbuk National University, Chungbuk 361-763, Republic of Korea, 6Department of Medicine, Eulji University, Daejeon 301-746, Republic of Korea |
| Bibliography |
Journal of Microbiology, 47(5),641-645, 2009,
|
| DOI |
|
| Key Words |
nuclear localization signal, DNA methylation, pathogenesis, K. pneumoniae |
| Abstract |
Nuclear targeting of bacterial proteins is an emerging pathogenic mechanism whereby bacterial proteins can interact with nuclear molecules and alter the physiology of host cells. The fully sequenced bacterial genome can predict proteins that target the nuclei of host cells based on the presence of nuclear localization
signal (NLS). In the present study, we predicted bacterial proteins with the NLS sequences from Klebsiella pneumoniae by bioinformatic analysis, and 13 proteins were identified as carrying putative NLS sequences. Among them, HsdM, a subunit of KpnAI that is a type I restriction-modification system found in K. pneumoniae, was selected for the experimental proof of nuclear targeting in host cells. HsdM carried
the NLS sequences, 7KKAKAKK13, in the N-terminus. A transient expression of HsdM-EGFP in COS-1 cells exhibited exclusively a nuclear localization of the fusion proteins, whereas the fusion proteins of HsdM with substitutions in residues lysine to alanine in the NLS sequences, 7AAAKAAA13, were localized in the cytoplasm. HsdM was co-localized with importin α in the nuclei of host cells. Recombinant HsdM alone methylated the eukaryotic DNA in vitro assay. Although HsdM tested in this study has not been considered to be a virulence factor, the prediction of NLS motifs from the full sequenced genome of bacteria extends
our knowledge of functional genomics to understand subcellular targeting of bacterial proteins. |
