Understanding the Regulation of DYRK Kinase

Dehury, Subhasis (2021) Understanding the Regulation of DYRK Kinase. Masters thesis, Indian Institute of Science Education and Research Kolkata.

Text (MS Dissertation of Subhasis Dehury (16MS006)) 16MS006_Thesis_file.pdf - Submitted Version Restricted to Repository staff only Download (35MB)

Abstract

Protein kinases are enzymes that play a vital role in the signalling process by phosphorylating a substrate through conserved catalytic residues. The kinases are highly regulated inside the cell with dysregulation, one of the leading causes of life-threatening complications like cancer, neurodegenerative and inflammatory diseases. Kinases are classified into tyrosine kinase and Ser/Thr kinase based on their ability to phosphorylate Tyr and Ser/Thr residue, respectively. Some kinases are known to phosphorylate; both these residues and are grouped under the Dual specific kinases. One of them is the DYRK family of kinases, a Ser/Thr CMGC family group, including MAPK, CDK, GSK3!.DYRK is an evolutionarily conserved family of kinase found from yeast to humans. They play a vital role in the cell-cycle progression, neural development, tumour suppressor. DYRK is known to autophosphorylate the tyrosine residue in the activation loop while it still expressing inside the cell. It loses its tyrosine kinase once it attains maturity and only phosphorylates Ser/Thr residue. There are many open questions related to its regulation. It is not clear how the kinase is regulated inside the cell and how it switches its confirmation once it attains maturity. I have employed and used biochemical techniques like coupled kinase assay in different experimental setups to characterize the DYRK2 and DYRK1A protein in this work. In order to understand the DYRK activation, the autophosphorylation assay was done to get insight into its autophosphorylation rate and how this activation rate varied with tyrosine kinase-like SRC. To identify the residue that might be playing an essential role in the kinase structure. I have used a Cytoscape network visualization application with a Residue interaction network generator that will map different non-covalent interactions happening inside the structure. The application uses graph theory techniques to perform the centrality analysis to identify the hub residue in the network. So mutating the residue might perturb the kinase structure and loses its activity. The graph theory techniques are not new to the kinase field. It has been employed in the past, which led to identifying and discovering the most important architecture of the kinases, the R-spine and C-spine. The aim is to identify a set of residues in the DYRK structure that regulates its function and its substrate switching action.

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