Analysis of Active Site Mutation in Casein Kinase 2 Involved in Okur-Chung’s Neuropathy

Devin Kelly, Dr. Ashok Bidwai, Department of Biology, West Virginia University, Morgantown, WV 26506

Okur-Chung’s neuropathy is a human neurodevelopmental disorder characterized by mental disabilities and dysmorphic facial features. Recent studies have led to discovery of ten distinct mutations in the human CSNK2A1 gene, which encodes the alpha subunit of the enzyme Casein Kinase 2 (CK2), that cause the onset of Okur-Chung’s neuropathy. CK2 is a highly conserved, ubiquitous protein kinase that plays a role in a wide variety of cellular functions. The means by which each of the ten known mutations leads to the onset of disease is unknown, and to develop potential treatments for this disease, the molecular mechanisms of each mutated CK2 alpha subunit must be analyzed. The mutation of isoleucine (Ile) at position 174 to methionine (Met) is of particular interest, as this mutation occurs in close proximity to the active site of the enzyme, where the binding of Mg2+-ATP enables donation of a phosphate group to activate CK2 for phosphorylation of substrates. Furthermore, Ile174 appears to be 100% conserved in all isoforms, indicating the importance and selectivity of this residue. It is proposed that the mutation of Ile174 to methionine should impair the function of CK2 due to changes in steric interactions, orientation, and available space within the active site. Due to the location of the mutation in the active site, interaction with binding partners like the regulatory beta subunits of CK2 should not be affected, while interactions with substrates that typically bind to the active site may be impaired. This hypothesis will be tested using yeast complementation assays in which mutated animal CK2 alpha will attempt to rescue yeast that have lost their own CK2 isoforms. Interactions between CK2 alpha, substrates, and binding partners will be assessed for the mutant enzyme through two-hybrid analyses (Gal4 fusions) in yeast cells.

Additional Abstract Information

Presenter: Devin Kelly

Institution: West Virginia University

Type: Poster

Subject: Biochemistry

Status: Approved

Time and Location

Session: Poster 2
Date/Time: Mon 3:00pm-4:00pm
Session Number: 2514