Discipline: Chemistry and Chemical Sciences
Subcategory: Biochemistry (not Cell and Molecular Biology and Genetics)
Chimere Nnatubeugo - Ball State University
Co-Author(s): Erica M. Johnson, Ball State University, Muncie, IN; Mary E. Konkle, Ball State University, Muncie, IN; Michael A. Menze, University of Louisville, Louisville, KY
MitoNEET is a recently discovered [2Fe-2S] protein that binds to the anti-diabetic drug pioglitazone. MitoNEET contains a unique ligation of three cysteines and one histidine, but its function is unknown. Since its discovery, studies have been conducted to understand the specific cellular function of mitoNEET and how its role in binding to pioglitazone affects insulin resistance in type II diabetic patients. Proposed functions include cellular respiration, electron transfer, and iron-sulfur cluster transfer. SDS-PAGE pull down experimentation has also indicated the formation of a disulfide bond between mitoNEET and glutamate dehydrogenase 1, an allosteric enzyme found in the mitochondrial matrix that catalyzes the reversible reaction of glutamate into α-ketoglutarate. In our lab, enzyme kinetics was used to analyze mitoNEET and bGDH1 with the addition of physiologically relevant ligands that were found to allosterically control bGDH1. These include activators leucine and ADP, and deactivators palmitoyl-CoA, epigallocatechin gallate (EGCG), and GTP. The data suggest that mitoNEET has a “rescue” effect on the overall rate of the reaction but does not completely overcome any deactivation of the enzyme. Likewise, order of addition of mitoNEET and the ligand does not appear to have an effect on the rate recovery. New findings suggest that NAD+ may alter the secondary structure of mitoNEET. Trials where NAD+ is added after mitoNEET has bound to bGDH1 may yield different results than those already obtained. Similar tests will also be replicated with NADP
Funder Acknowledgement(s): Louis Stokes Alliance for Minority Participation NSF #1618408; National Science Foundation #1609440
Faculty Advisor: Dr. Mary Konkle, firstname.lastname@example.org
Role: Preliminary analysis of the relationship between mitoNEET and GDH was done prior to my involvemen in this lab. Past students under the instruction of my PI, Dr. Mary Konkle, have produced data on ADP and GTP with the addition of NAD+. I and my partner Erica Johnson replicated these results and completed the data for the rest the ligands. I will continue to work with these ligands with the addition of NADP and NAD+ in varying orders.