Research project in the OPUS program of the National Science Centre on „The mechanism of RNA recognition by KH-domain proteins KhpA and KhpB from Streptococcus pneumoniae (No. 2022/47/B/NZ1/01665)
RNA-binding proteins participate in the mechanisms of control of gene expression, which are dependent on regulatory RNAs. In Gram-negative bacteria, such as Escherichia coli and Salmonella enterica, this role is fulfilled, among others, by proteins Hfq and ProQ. The roles of these proteins have been widely studied, and it is known that by binding RNAs they affect RNA lifetimes, and also that they help regulatory RNAs to find mRNAs that they control. On the other hand, very little is known about RNA-binding proteins, which cooperate with regulatory RNAs in Gram-positive bacteria, such as Streptococcus pneumoniae.
It has been recently found that there are two RNA-binding proteins, named KhpA and KhpB, that are present in many Gram-positive bacteria, but not in Gram -negative ones [1]. KhpA and KhpB have in their structure RNA binding domains. In KhpA it is a single KH domain, while in KhpB there are two domains: KH domain and R3H. Such domains are also present in other RNA-binding proteins in bacteria and in higher organisms. Interestingly, in almost all of these bacterial species KhpA and KhpB are present together. It was found that in Streptococcus pneumoniae, and also in other species, KhpA and KhpB bind the same RNAs. This suggests that they cooperate with one another. It was also found that they participate in the regulation of the process of cell division, because the deletion of their genes changed the shape of cells of S. pneumoniae.
Very little is known about how KhpA and KhpB recognize RNAs, and why both of them have to participate in this process. We expect that the studies planned in this project will allow to elucidate how KhpA and KhpB, which belong to a new family of RNA binding proteins, contribute to the biological processes dependent on RNA molecules. Because KhpA and KhpB participate in the process of cell division in S. pneumoniae the conclusions of the planned studies may also provide new insights into the regulation of this important mechanism, which may be useful for the design of new strategies of controlling bacterial growth.
References
- Olejniczak M, Jiang X, Basczok MM, Storz G. KH domain proteins: Another family of bacterial RNA matchmakers? Mol Microbiol. (2022) 117(1):10-19 Pubmed