Research Projects

Nucleolin (NCL) is a crucial protein involved in various cellular processes, including ribosome assembly, mRNA stability, and microRNA processing. Its four RNA binding domains (RRMs) and highly disordered RG/RGG domain at its C-terminal end facilitate its sub-cellular localization. The ability of NCL to interact with and bind to DNA/RNA is influenced by the interplay between different RBDs and the C-terminal, which can be modulated to provide specificity. However, the domain characteristics that provide this specificity through which NCL can identify its substrates are still lacking. The proposed study aims to determine domain organizational changes in NCL that influence DNA/RNA recognition and regulate downstream processes through phase separation. Recent studies have shown that NCL can bind to G-quadruplex structures in human telomeric DNA and TERRA RNA. The differences in recognition and binding of NCL towards different nucleic acid substrates lie at the level of individual RRM domains, with RRM1 acting as an anchor and mediating the creation of new binding interfaces with the addition of more domains. Experiments will include docking and mutagenesis studies to identify specific amino acid residues interacting with Telo and TERRA G-quadruplexes, biophysical approaches like ITC and MST to characterize binding experiments, and RNA immunoprecipitation to find the global RNA transcriptome that NCL can bind to. NCL's extreme binding preference towards G-quadruplex structures makes it a valuable protein for therapeutic targets, such as AS1411, the anti-nucleolin aptamer used for targeted drug delivery in cancer cells.