Blue Native Polyacrylamide Gel Electrophoresis: A Powerful Diagnostic Tool for the Detection of Assembly Defects in the Enzyme Complexes of Oxidative Phosphorylation

Abstract

The bulk of ATP consumed by various cellular processes is normally produced by five multimeric protein complexes embedded within the inner mitochondrial membrane in a process known as oxidative phosphorylation (OXPHOS). Mutations that impair the assembly, and therefore the function, of one or more of these enzyme complexes severely compromise energy homeostasis and are a frequent cause of human disease. Because mitochondrial diseases are a clinically heterogeneous group of genetic disorders, biochemical and molecular diagnostic analyses are often an essential first step in confirming suspected cases and ultimately aid in identifying the genetic basis of disease in affected individuals. Blue native polyacrylamide gel electrophoresis has proven to be particularly invaluable in this regard, providing researchers with a facile approach for analyzing the assembly, total abundance, and residual enzymatic activity of individual OXPHOS complexes. As such, this technique has greatly facilitated the more thorough molecular genetic investigation of diseases that are caused by isolated and combined deficiencies in the enzymes that comprise the OXPHOS system.