title: Dynamic Visualization of mTORC1 Activity in Living Cells.
abstract: The mechanistic target of rapamycin complex 1 (mTORC1) senses diverse signals to regulate cell growth and metabolism. It has become increasingly clear that mTORC1 activity is regulated in time and space inside the cell, but direct interrogation of such spatiotemporal regulation is challenging. Here, we describe a genetically encoded mTORC1 activity reporter (TORCAR) that exhibits a change in FRET in response to phosphorylation by mTORC1. Co-imaging mTORC1 activity and calcium dynamics revealed that a growth-factor-induced calcium transient contributes to mTORC1 activity. Dynamic activity maps generated with the use of subcellularly targeted TORCAR uncovered mTORC1 activity not only in cytosol and at the lysosome but also in the nucleus and at the plasma membrane. Furthermore, a wide distribution of activities was observed upon growth factor stimulation, whereas leucine ester, an amino acid surrogate, induces more compartmentalized activities at the lysosome and in the nucleus. Thus, mTORC1 activities are spatiotemporally regulated in a signal-specific manner.
authors.affiliation: Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
authors.forename: Xin
authors.initials: X
authors.lastname: Zhou
authors.affiliation: Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
authors.forename: Terri L
authors.initials: TL
authors.lastname: Clister
authors.affiliation: Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
authors.forename: Pamela R
authors.initials: PR
authors.lastname: Lowry
authors.affiliation: Department of Physiology and Center for Metabolism and Obesity Research, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
authors.forename: Marcus M
authors.initials: MM
authors.lastname: Seldin
authors.affiliation: Department of Physiology and Center for Metabolism and Obesity Research, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
authors.forename: G William
authors.initials: GW
authors.lastname: Wong
authors.affiliation: Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; The Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Oncology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. Electronic address: jzhang32@jhmi.edu.
authors.forename: Jin
authors.initials: J
authors.lastname: Zhang