Tuberous sclerosis-2 (TSC2) regulates the stability of death-associated protein kinase-1 (DAPK) through a lysosome-dependent degradation pathway Yao Lin1, Paul Henderson1,2, Susanne Pettersson1, Jack Satsangi1, Ted Hupp1 and Craig Stevens1 1 University of Edinburgh, Institute of Genetics and Molecular Medicine, UK 2 Department of Child Life and Health, University of Edinburgh, UK Keywords We previously identified a novel interaction between tuberous sclerosis-2 DAPK; degradation; lysosome; mTORC1; (TSC2) and death-associated protein kinase-1 (DAPK), the consequence TSC2 being that DAPK catalyses the inactivating phosphorylation of TSC2 to stimulate mammalian target of rapamycin complex 1 (mTORC1) activity. Correspondence C. Stevens, University of Edinburgh, We now report that TSC2 binding to DAPK promotes the degradation of Institute of Genetics and Molecular DAPK. We show that DAPK protein levels, but not gene expression, Medicine, Edinburgh, EH4 2XR, UK inversely correlate with TSC2 expression. Furthermore, altering mTORC1 Fax: +44 131 651 1085 activity does not affect DAPK levels, excluding indirect effects of TSC2 on Tel: +44 131 651 1025 DAPK protein levels through changes in mTORC1 translational control. E-mail:
[email protected] We provide evidence that the C-terminus regulates TSC2 stability and is required for TSC2 to reduce DAPK protein levels. Importantly, using a (Received 28 July 2010, revised 7 October 2010, accepted 11 November 2010) GTPase-activating protein–dead missense mutation of TSC2, we demon- strate that the effect of TSC2 on DAPK is independent of GTPase-activat- doi:10.1111/j.1742-4658.2010.07959.x ing protein activity. TSC2 binds to the death domain of DAPK and we show that this interaction is required for TSC2 to reduce DAPK protein levels and half-life.