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Kinase Activity of PAR1b, Which Mediates Nuclear Translocation of the BRCA1 Tumor Suppressor, Is Potentiated by Nucleic Acid-Mediated PAR1b Multimerization
Title: | Kinase Activity of PAR1b, Which Mediates Nuclear Translocation of the BRCA1 Tumor Suppressor, Is Potentiated by Nucleic Acid-Mediated PAR1b Multimerization |
Authors: | Nishikawa, Hiroko Browse this author | Christiany, Priscillia Browse this author | Hayashi, Takeru Browse this author | Iizasa, Hisashi Browse this author | Yoshiyama, Hironori Browse this author | Hatakeyama, Masanori Browse this author →KAKEN DB |
Keywords: | PAR1b | multimerization | nucleic acids | kinase activation | EBER | gastric cancer |
Issue Date: | Jun-2022 |
Publisher: | MDPI |
Journal Title: | International Journal of Molecular Sciences |
Volume: | 23 |
Issue: | 12 |
Start Page: | 6634 |
Publisher DOI: | 10.3390/ijms23126634 |
Abstract: | PAR1b is a cytoplasmic serine/threonine kinase that controls cell polarity and cell-cell interaction by regulating microtubule stability while mediating cytoplasmic-to-nuclear translocation of BRCA1. PAR1b is also a cellular target of the CagA protein of Helicobacter pylori, which leads to chronic infection causatively associated with the development of gastric cancer. The CagA-PAR1b interaction inactivates the kinase activity of PAR1b and thereby dampens PAR1b-mediated BRCA1 phosphorylation, which reduces the level of nuclear BRCA1 and thereby leads to BRCAness and BRCAness-associated genome instability underlying gastric carcinogenesis. While PAR1b can multimerize within the cells, little is known about the mechanism and functional role of PAR1b multimerization. We found in the present study that PAR1b was multimerized in vitro by binding with nucleic acids (both single- and double-stranded DNA/RNA) via the spacer region in a manner independent of nucleic-acid sequences, which markedly potentiated the kinase activity of PAR1b. Consistent with these in vitro observations, cytoplasmic introduction of double-stranded DNA or expression of single-stranded RNA increased the PAR1b kinase activity in the cells. These findings indicate that the cytoplasmic DNA/RNA contribute to nuclear accumulation of BRCA1 by constitutively activating/potentiating cytoplasmic PAR1b kinase activity, which is subverted in gastric epithelial cells upon delivery of H. pylori CagA oncoprotein. |
Type: | article |
URI: | http://hdl.handle.net/2115/86795 |
Appears in Collections: | 遺伝子病制御研究所 (Institute for Genetic Medicine) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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