tailieunhanh - Báo cáo khoa học: Tuberous sclerosis-2 (TSC2) regulates the stability of death-associated protein kinase-1 (DAPK) through a lysosome-dependent degradation pathway

We previously identified a novel interaction between tuberous sclerosis-2 (TSC2) and death-associated protein kinase-1 (DAPK), the consequence being that DAPK catalyses the inactivating phosphorylation of TSC2 to stimulate mammalian target of rapamycin complex 1 (mTORC1) activity. | IFEBS Journal 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 DAPK degradation lysosome mTORC1 TSC2 Correspondence C. Stevens University of Edinburgh Institute of Genetics and Molecular Medicine Edinburgh EH4 2XR UK Fax 44 131 651 1085 Tel 44 131 651 1025 E-mail Received 28 July 2010 revised 7 October 2010 accepted 11 November 2010 doi We previously identified a novel interaction between tuberous sclerosis-2 TSC2 and death-associated protein kinase-1 DAPK the consequence being that DAPK catalyses the inactivating phosphorylation of TSC2 to stimulate mammalian target of rapamycin complex 1 mTORC1 activity. We now report that TSC2 binding to DAPK promotes the degradation of DAPK. We show that DAPK protein levels but not gene expression inversely correlate with TSC2 expression. Furthermore altering mTORC1 activity does not affect DAPK levels excluding indirect effects of TSC2 on DAPK protein levels through changes in mTORC1 translational control. We provide evidence that the C-terminus regulates TSC2 stability and is required for TSC2 to reduce DAPK protein levels. Importantly using a GTPase-activating protein-dead missense mutation of TSC2 we demonstrate that the effect of TSC2 on DAPK is independent of GTPase-activat-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. Finally we show that DAPK is regulated by the lysosome pathway and that lysosome inhibition blocks TSC2-mediated degradation of DAPK. Our study therefore establishes important functions of TSC2 and the .