Study on ubiquitination of proteins of the MRPS18 family in vitro
Abstract
Aim. It is known that in cancerous cells of childhood tumors the pathological changes often include inactivation of the TP53 and RB-E2F1 cellular pathways. One of the proteins controlling the latter pathway is MRPS18-2, that belongs to a family of mitochondrial ribosomal proteins MRPS18. It is important, to study the stability of proteins of this family and their ubiquitination, that might help to conclude about the functional properties of these proteins and their role in cell transformation. Methods. Cloning of cDNA in FLAG vector for expression of fusion proteins, transfection of human tumor cells MCF7, study on cellular localization of MRPS18 family proteins and their ubiquitination by fluorescence microscopy, using specific antibodies. Results. The FLAG-MRPS18-1 and FLAG-MRPS18-3 fusion proteins are partially co-localizing with the HA-Ub fusion protein in the cytoplasm of MCF7 cells. The FLAG-MRPS18-2 protein is localized also in the nucleus. Conclusions. Nuclear localization of the FLAG-MRPS18-2 protein may indicate its additional functions in the cell: due to the interaction with the RB protein and the positive effect on mono-ubiquitination of histone H2B, the MRPS18-2 protein may be involved in the regulation of chromatin structure.
References
Penzo M., Montanaro L., Trere D., Derenzini M. The Ribosome Biogenesis—Cancer Connection. Cells. 2019. Vol. 8. P. 55. doi: 10.3390/cells8010055.
Greber B.J., Ban N. Structure and function of the mitochondrial ribosome. Annu. Rev. Biochem. 2016. Vol. 85. P. 103–132.
Greber B.J., Boehringer D., Leibundgut M., Bieri P., Leitner A., Schmitz N., Aebersold R., Ban N. The complete structure of the large subunit of the mammalian mitochondrial ribosome. Nature. 2014. Vol. 515. P. 283–286. doi: 10.1038/nature13895.
Mushtaq M., Ali R.H., Kashuba V., Klein G., Kashuba E. S18 family of mitochondrial ribosomal proteins: evolutionary history and Gly132 polymorphism in colon carcinoma. Oncotarget. 2016. Vol. 7. P. 55649–55662.
Mints M., Mushtaq M., Iurchenko N., Kovalevska L., Stip M.C., Budnikova D., Andersson S., Polischuk L., Buchynska L., Kashuba E. Mitochondrial ribosomal protein S18-2 is highly expressed in endometrial cancers along with free E2F1. Oncotarget. 2016. Vol. 7. P. 22150–22158. doi: 10.18632/oncotarget.7905.
Mushtaq M., Jensen L., Davidsson S., Grygoruk O.V., Andren O., Kashuba V., Kashuba E. The MRPS18-2 protein levels correlate with prostate tumor progression and it induces CXCR4-dependent migration of cancer cells. Sci Rep. 2018. Vol. 8. P. 2268. doi: 10.1038/s41598-018-20765-8.
Buivydiene A., Liakina V., Valantinas J., Norkuniene J., Mockiene E., Jokubauskiene S., Smaliukiene R., Jancoriene L., Ko-valevska L., Kashuba E. Expression levels of the uridine-cytidine kinase like-1 protein as a novel prognostic factor for Hepatitis C virus-associated hepatocellular carcinomas. Acta Naturae. 2017. Vol. 9. P. 108–114.
Buchynska L.G., Iurchenko N.P., Kashuba E.V., Brieieva O.V., Glushchenko N.M., Mints M., Lukianova N.Y., Chekhun V.F. Overexpression of the mitochondrial ribosomal protein S18-2 in the invasive breast carcinomas. Exp Oncol. 2018. Vol. 40. P. 303–308.
Kovalevska L., Kashuba E. Expression pattern of MRPS18 family genes in malignantly transformed b-cells. Exp oncol. 2020. Vol. 42. P. 295–299.
Kovalevska L.M., Malysheva T.A., Kalman S.S., Rozumenko A.V., Verbova L.V., Rozumenko V.D., Kashuba E.V. Expression pattern of MRPS18 family genes in gliomas. Exp Oncol. 2021. Vol. 43. P. 204–208. doi: 10.32471/exp-oncology.2312-8852.vol-43-no-3.16461.
Kashuba E., Yurchenko M., Yenamandra S.P., Snopok B., Isaguliants M., Szekely L., Klein G. EBV-encoded EBNA-6 binds and targets MRS18–2 to the nucleus, resulting in the disruption of pRb-E2F1 complexes. Proc Natl Acad Sci USA. 2008. Vol. 105. P. 5489–5494.
Mushtaq M., Gaza H.V., Kashuba E.V. Role of the RB-Interacting Proteins in Stem Cell Biology. Adv Cancer Res. 2016. Vol. 131. P. 133–157.
Mushtaq M., Kovalevska L., Darekar S., Abramsson A., Zetterberg H., Kashuba V., Klein G., Arsenian-Henriksson M., Kashu-ba E. Cell stemness is maintained upon concurrent expression of RB and the mitochondrial ribosomal protein S18-2. Proc Natl Acad Sci USA. 2020. Vol. 117. P. 15673–15683. doi: 10.1073/pnas.1922535117.