Investigating role of plumbagin in preventing neurodegenerative diseases via inhibiting microtubule affinity regulating kinase 4

•Hyperphosphorylation of tau by MARK4 is a critical event in the pathogenesis of AD.•Inhibiting MARK4 by plumbagin is an attractive strategy for AD therapeutics.•MD simulation studies suggested the formation of a stable MARK4-plumbagin complex.•Fluorescence and ITC studies revealed strong binding affinity of plumbagin to MARK4.•Plumbagin inhibits the kinase activity of MARK4 with an IC50 value of 5.2 µM, and thus implicated in AD therapeutics. Microtubule affinity regulating kinase 4 (MARK4) is associated with the progression of neurodegeneration, cancer, cardiovascular diseases, obesity and other life-threatening conditions. MARK4 is an attractive therapeutic target; however, inhibitors against the kinase are sparse. Natural compounds are a part of our dietary routine and have been used as medicines for ages with the most negligible side effects. In this study, we have selected the naphthoquinone derivative, Plumbagin (PBG). The naturally occurring naphthoquinone has been studied for its inhibitory action against MARK4 and its binding mechanism to the protein. Binding studies employing computational and spectroscopic methods have been used to assess the binding of the compound with MARK4. Critical residues of the protein showed involvement in the binding process, and the protein–ligand binding affinity was estimated to be 106. The inhibitory potential of PBG against MARK4 was also evaluated, with an IC50 value of 5.2 µM. All-atom molecular dynamics (MD) simulation study also showed a stable protein–ligand complex formation, stabilized in the trajectories, and very few conformational changes were observed.