Structure of the TSC2 GAP Domain: Mechanistic Insight into Catalysis and Pathogenic Mutations

Patrick Hansmann; Anne Brückner; Stephan Kiontke; Bianca Berkenfeld; Guiscard Seebohm; Pascal Brouillard; Miikka Vikkula; Floor E Jansen; Mark Nellist; Andrea Oeckinghaus; Daniel Kümmel

doi:10.1016/j.str.2020.05.008

Structure of the TSC2 GAP Domain: Mechanistic Insight into Catalysis and Pathogenic Mutations

Structure. 2020 Aug 4;28(8):933-942.e4. doi: 10.1016/j.str.2020.05.008. Epub 2020 Jun 4.

Authors

Affiliations

¹ Westfälische Wilhelms-Universität, Institute of Biochemistry, Wilhelm Klemm-Str. 2, 48149 Münster, Germany.
² Westfälische Wilhelms-Universität, Institute of Biochemistry, Wilhelm Klemm-Str. 2, 48149 Münster, Germany; Westfälische Wilhelms-Universität, Institute of Molecular Tumor Biology, Robert-Koch-Str. 43, 48149 Münster, Germany.
³ Philipps-Universität Marburg, Faculty of Biology, Department of Plant Physiology and Photobiology, Karl-von-Frisch-Str. 8, 35032 Marburg, Germany.
⁴ University Hospital Münster, Institute for Genetics of Heart Diseases, Department of Cardiovascular Medicine, Robert-Koch-Str. 45, 48149 Münster, Germany.
⁵ Université Catholique de Louvain, de Duve Institute, Human Molecular Genetics, Brussels, Belgium.
⁶ Université Catholique de Louvain, de Duve Institute, Human Molecular Genetics, Brussels, Belgium; WELBIO (Walloon Excellence in Lifesciences and Biotechnology), de Duve Institute, Université Catholique de Louvain, Brussels, Belgium.
⁷ Department of Child Neurology, Brain Center UMC Utrecht, Utrecht, the Netherlands.
⁸ Department of Clinical Genetics, Erasmus Medical Center, Wytemaweg 80, 3015 CN Rotterdam, the Netherlands.
⁹ Westfälische Wilhelms-Universität, Institute of Molecular Tumor Biology, Robert-Koch-Str. 43, 48149 Münster, Germany.
¹⁰ Westfälische Wilhelms-Universität, Institute of Biochemistry, Wilhelm Klemm-Str. 2, 48149 Münster, Germany. Electronic address: daniel.kuemmel@wwu.de.

PMID: 32502382
DOI: 10.1016/j.str.2020.05.008

Abstract

The TSC complex is the cognate GTPase-activating protein (GAP) for the small GTPase Rheb and a crucial regulator of the mechanistic target of rapamycin complex 1 (mTORC1). Mutations in the TSC1 and TSC2 subunits of the complex cause tuberous sclerosis complex (TSC). We present the crystal structure of the catalytic asparagine-thumb GAP domain of TSC2. A model of the TSC2-Rheb complex and molecular dynamics simulations suggest that TSC2 Asn1643 and Rheb Tyr35 are key active site residues, while Rheb Arg15 and Asp65, previously proposed as catalytic residues, contribute to the TSC2-Rheb interface and indirectly aid catalysis. The TSC2 GAP domain is further stabilized by interactions with other TSC2 domains. We characterize TSC2 variants that partially affect TSC2 functionality and are associated with atypical symptoms in patients, suggesting that mutations in TSC1 and TSC2 might predispose to neurological and vascular disorders without fulfilling the clinical criteria for TSC.

Keywords: GTPase-activating protein; Rheb; TSC; mTORC1.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Catalytic Domain*
HEK293 Cells
Humans
Molecular Dynamics Simulation
Mutation, Missense*
Ras Homolog Enriched in Brain Protein / chemistry
Ras Homolog Enriched in Brain Protein / metabolism
Tuberous Sclerosis / genetics*
Tuberous Sclerosis Complex 2 Protein / chemistry*
Tuberous Sclerosis Complex 2 Protein / genetics
Tuberous Sclerosis Complex 2 Protein / metabolism

Substances

RHEB protein, human
Ras Homolog Enriched in Brain Protein
TSC2 protein, human
Tuberous Sclerosis Complex 2 Protein