title: Structure-function analysis of NEET proteins uncovers their role as key regulators of iron and ROS homeostasis in health and disease.
abstract: A novel family of 2Fe-2S proteins, the NEET family, was discovered during the last decade in numerous organisms, including archea, bacteria, algae, plant and human; suggesting an evolutionary-conserved function, potentially mediated by their CDGSH Iron-Sulfur Domain. In human, three NEET members encoded by the CISD1-3 genes were identified. The structures of CISD1 (mitoNEET, mNT), CISD2 (NAF-1), and the plant At-NEET uncovered a homodimer with a unique "NEET fold", as well as two distinct domains: a beta-cap and a 2Fe-2S cluster-binding domain. The 2Fe-2S clusters of NEET proteins were found to be coordinated by a novel 3Cys:1His structure that is relatively labile compared to other 2Fe-2S proteins and is the reason of the NEETs' clusters could be transferred to apo-acceptor protein(s) or mitochondria. Positioned at the protein surface, the NEET's 2Fe-2S's coordinating His is exposed to protonation upon changes in its environment, potentially suggesting a sensing function for this residue. Studies in different model systems demonstrated a role for NAF-1 and mNT in the regulation of cellular iron, calcium and ROS homeostasis, and uncovered a key role for NEET proteins in critical processes, such as cancer cell proliferation and tumor growth, lipid and glucose homeostasis in obesity and diabetes, control of autophagy, longevity in mice, and senescence in plants. Abnormal regulation of NEET proteins was consequently found to result in multiple health conditions, and aberrant splicing of NAF-1 was found to be a causative of the neurological genetic disorder Wolfram Syndrome 2. Here we review the discovery of NEET proteins, their structural, biochemical and biophysical characterization, and their most recent structure-function analyses. We additionally highlight future avenues of research focused on NEET proteins and propose an essential role for NEETs in health and disease. This article is part of a Special Issue entitled: Fe/S proteins: Analysis, structure, function, biogenesis and diseases.
authors.affiliation: The Alexander Silberman Life Science Institute and the Wolfson Centre for Applied Structural Biology, Hebrew University of Jerusalem, Edmond J. Safra Campus at Givat Ram, Jerusalem 91904, Israel.
authors.forename: Sagi
authors.initials: S
authors.lastname: Tamir
authors.affiliation: Department of Chemistry and Biochemistry, University of California at San Diego, La Jolla, CA 92093, USA.
authors.forename: Mark L
authors.initials: ML
authors.lastname: Paddock
authors.affiliation: The Alexander Silberman Life Science Institute and the Wolfson Centre for Applied Structural Biology, Hebrew University of Jerusalem, Edmond J. Safra Campus at Givat Ram, Jerusalem 91904, Israel.
authors.forename: Merav
authors.initials: M
authors.lastname: Darash-Yahana-Baram
authors.affiliation: Department of Biology, University of North Texas, Denton, TX 76203, USA.
authors.forename: Sarah H
authors.initials: SH
authors.lastname: Holt
authors.affiliation: The Alexander Silberman Life Science Institute and the Wolfson Centre for Applied Structural Biology, Hebrew University of Jerusalem, Edmond J. Safra Campus at Givat Ram, Jerusalem 91904, Israel.
authors.forename: Yang Sung
authors.initials: YS
authors.lastname: Sohn
authors.affiliation: The Alexander Silberman Life Science Institute and the Wolfson Centre for Applied Structural Biology, Hebrew University of Jerusalem, Edmond J. Safra Campus at Givat Ram, Jerusalem 91904, Israel.
authors.forename: Lily
authors.initials: L
authors.lastname: Agranat
authors.affiliation: The Alexander Silberman Life Science Institute and the Wolfson Centre for Applied Structural Biology, Hebrew University of Jerusalem, Edmond J. Safra Campus at Givat Ram, Jerusalem 91904, Israel.
authors.forename: Dorit
authors.initials: D
authors.lastname: Michaeli
authors.affiliation: Department of Chemistry and Biochemistry, University of California at San Diego, La Jolla, CA 92093, USA.
authors.forename: Jason T
authors.initials: JT
authors.lastname: Stofleth
authors.affiliation: Department of Chemistry and Biochemistry, University of California at San Diego, La Jolla, CA 92093, USA.
authors.forename: Colin H
authors.initials: CH
authors.lastname: Lipper
authors.affiliation: Center for Theoretical Biological Physics, Rice University, Houston, TX 77050, USA; Department of Physics and Astronomy, Rice University, Houston, TX 77050, USA; Department of Chemistry, Rice University, Houston, TX 77050, USA; Department of Biochemistry and Cell Biology, Rice University, Houston, TX 77050, USA.
authors.forename: Faruck
authors.initials: F
authors.lastname: Morcos
authors.affiliation: The Alexander Silberman Life Science Institute and the Wolfson Centre for Applied Structural Biology, Hebrew University of Jerusalem, Edmond J. Safra Campus at Givat Ram, Jerusalem 91904, Israel.
authors.forename: Ioav Z
authors.initials: IZ
authors.lastname: Cabantchik
authors.affiliation: Center for Theoretical Biological Physics, Rice University, Houston, TX 77050, USA; Department of Physics and Astronomy, Rice University, Houston, TX 77050, USA; Department of Chemistry, Rice University, Houston, TX 77050, USA; Department of Biochemistry and Cell Biology, Rice University, Houston, TX 77050, USA.
authors.forename: Jose' N
authors.initials: JN
authors.lastname: Onuchic
authors.affiliation: Department of Chemistry and Biochemistry, University of California at San Diego, La Jolla, CA 92093, USA.
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Jennings
authors.affiliation: Department of Biology, University of North Texas, Denton, TX 76203, USA.
authors.forename: Ron
authors.initials: R
authors.lastname: Mittler
authors.affiliation: The Alexander Silberman Life Science Institute and the Wolfson Centre for Applied Structural Biology, Hebrew University of Jerusalem, Edmond J. Safra Campus at Givat Ram, Jerusalem 91904, Israel. Electronic address: rachel@mail.huji.ac.il.
authors.forename: Rachel
authors.initials: R
authors.lastname: Nechushtai
mesh_terms: D000595:Amino Acid Sequence; D020022:Genetic Predisposition to Disease / Q000235:genetics; D006706:Homeostasis; D006801:Humans; D007501:Iron / Q000378:metabolism*; D024101:Mitochondrial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017382:Reactive Oxygen Species / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid
chemical_list: C525595:CISD1 protein, human; D024101:Mitochondrial Proteins; D017382:Reactive Oxygen Species; D007501:Iron
keywords: 2Fe–2S cluster; Cancer; Cluster donor/acceptor protein; Homeostasis; Mitochondria; Obesity and diabetes; Wolfram Syndrome 2