Structural Studies on Calcium/calmodulin-dependent Activation of Eukaryotic Elongation Factor 2 Kinase

<p>Eukaryotic elongation factor 2 kinase (eEF-2K) is a key modulator of the rate of protein synthesis. Activated by calcium-loaded calmodulin (Ca²⁺-CaM), eEF-2K phosphorylates its only known physiological substrate, eEF-2, on a specific threonine residue (Thr-56). Phosphorylated eEF-2 has reduced affinity for the ribosome, and results in a significant decrease in the rate of translation elongation. Modulation of the rate of translation elongation plays a crucial role in proteostasis – adequate regulation of protein synthesis, protein folding, and protein degradation that greatly influences cellular growth and survival. Binding of Ca²⁺-CaM triggers activation of eEF-2K and remains intact to facilitate the substrate phosphorylation, acting as a cofactor of the enzyme. Despite its importance, how the binding of Ca²⁺-CaM leads to activation remains poorly understood.</p> <p>We employed various biophysical tools, such as nuclear magnetic resonance (NMR) spectroscopy and isothermal titration calorimetry (ITC), coupled with mutational strategies to characterize structural and thermodynamic nature of the binding of Ca²⁺-CaM onto eEF-2K. Our data clarify the roles of Ca²⁺ and each lobe of CaM that provide mechanistic insight into the structural regulation of eEF-2K mediated by the binding of Ca²⁺-CaM.</p>

Name thesis:degree_name

Doctor of Philosophy

Level thesis:degree_level

Doctoral

Discipline thesis:degree_discipline

Biochemistry

Grantor

The Graduate School and University Center of The City University of New York

Year dc:date.available

2019

Author dc:creator

• Lee, Kwangwoon

Advisor dc:contributor.advisor

• Ranajeet Ghose

Committee members dc:contributor.committeemember

• Kevin Dalby
• David Jeruzalmi
• Reza Khayat
• Ming-Ming Zhou

• Biochemistry
• Biophysics
• Structural Biology
• calmodulin
• eEF-2K
• NMR
• ITC

Repository record dc:identifier

https://academicworks.cuny.edu/gc_etds/3037

OAI identifier oai:identifier

oai:academicworks.cuny.edu:gc_etds-4102