Ataxia-telangiectasia (A-T) is an autosomal recessive disorder characterized by cerebellar ataxia and oculocutaneous telangiectasias. The gene mutated in this disease, Atm (A-T mutated), encodes a serine/threonine protein kinase that has been traditionally considered to be a nuclear protein controlling cell-cycle progression. However, many of the growth abnormalities observed in patients with A-T, including neuronal degeneration and insulin resistance, remain difficult to explain with nuclear localization of ATM. Here, recent advances in elucidating the cytoplasmic localization and function of ATM are reviewed. Particular attention is given to the role of ATM in insulin signaling and Akt activation. The potential for cytoplasmic ATM protein kinase to be an emerging therapeutic target for treating diabetes, cancer and neuronal degeneration is discussed.
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We would like to thank Dr David Pearce and Dr Alex Rabinovitch (Sanford Research/USD) for their helpful comments on this manuscript. Research in the authors’ laboratory was supported by an Innovation Award from the American Diabetes Association and a research grant from the A–T Children's Project.