The NEET family recently emerged as an important class of proteins that are involved in multiple pathologies, including mitochondrial integrity, diabetes, and aging-related diseases. Although two family members, MitoNEET and NAF-1, have high structural similarity, studies and literature reports indicate that the two proteins are involved in different pathologies; while MitoNEET is involved in diabetes, NAF-1 is a key protein in mediating both longevity and skeletal muscle disorders in mice. Both MitoNEET and NAF-1 are essential factors in maintaining mitochondrial integrity and major cellular processes, such as autophagy and oxidative capacity.

MitoNEET and NAF-1 constitute a novel family of [2Fe-2S] cluster containing proteins because of their unique coordination geometry, and they are generating high interest due to their unexpected binding of TZD diabetes drugs in a completely distinct fashion from the paradigm established by the TZD/nuclear transcription factor target PPAR-γ in the treatment of Type-II diabetes. While standard TZD drugs that target PPAR-γ can result in a host of undesirable side effects, MitoNEET targeting does not appear to suffer these limitations.

Here, we report our success in tuning the E_M of the [2Fe-2S] center of the outer mitochondrial membrane protein MitoNEET over a range of 700 mV, which is the largest E_M range engineered in an FeS protein and, importantly, spans the cellular redox range. We have also learned that NAF-1 has multiple in vivo binding partners, identified several potential binding partners, and shown that NAF-1 is likely highly involved in autophagy, apoptosis, and general cellular stability, longevity, and integrity.