Abstract: A nanosensor for detecting and quantifying lactate in different types of samples, such as tissues, intra-cellular and subcellular compartments, with high spatial and temporal resolution is disclosed. Methods comprising use of the nanosensor for quantifying the activity of lactate transporters, rates of cellular lactate production and cellular lactate consumption, and rate of mitochondrial pyruvate consumption are also disclosed. Methods for quantifying the transformation in energy metabolism that characterizes cancer cells with single-cell resolution and for detecting interference of candidate drugs with mitochondrial energetics are additionally disclosed.

Abstract: A novel class of transporter protein, referred to as SWEET, GLUE or Glü, is disclosed. These transporters provide a novel system for the transportation of sugars across membranes within a cell and between the inside and outside of a cell. Such transporters are useful for understanding and altering the sugar concentration within certain organs of an organism, and within certain organelles within the cell. These transporters are also useful in protecting plants from a pathogen attack.

Abstract: The present disclosure provides fluorescent polypeptides containing a fusion of a circularly permuted, first fluorescent protein and a second fluorescent protein, the first fluorescent protein containing a first fluorescent moiety and the second fluorescent protein containg a second fluorescent moiety, wherein the second fluorescent protein is contained in the circularly permuted first fluorescent protein to form a cassette that can be inserted into sites within a sensing protein of interest to form novel biosensors; alternatively, the reference domain can be inserted into an existing single-fluorescent protein-based, intensiometric biosensor in order to make a ratiometric biosensor in one cloning step; nucleic acid sequences encoding the fluorescent polypeptides, fluorescent sensors including the fluorescent polypeptides, and methods of making and using same are described herein.

Abstract: A novel class of transporter protein, referred to as SWEET, GLUE or Glü, is disclosed. These transporters provide a novel system for the transportation of sugars across membranes within a cell and between the inside and outside of a cell. Such transporters are useful for understanding and altering the sugar concentration within certain organs of an organism, and within certain organelles within the cell. These transporters are also useful in protecting plants from a pathogen attack.

Abstract: Intramolecular biosensors are disclosed, including PBP-based biosensors, comprising a ligand binding domain fused to donor and fluorescent moieties that permit detection and measurement of Fluorescence Resonance Energy Transfer upon binding ligand. At least one of the donor and fluorescent moieties may be internally fused to the biosensor such that both ends of the internally fused fluorophore are fixed. In addition, methods of improving the sensitivity of terminally fused biosensors are provided. The biosensors of the invention are useful for the detection and quantification of ligands in vivo and in culture.

Abstract: A novel class of transporter protein, referred to as SWEET, GLUE or Glü, is disclosed. These transporters provide a novel system for the transportation of sugars across membranes within a cell and between the inside and outside of a cell. Such transporters are useful for understanding and altering the sugar concentration within certain organs of an organism, and within certain organelles within the cell. These transporters are also useful in protecting plants from a pathogen attack.

Abstract: The present invention relates to methods of increasing the levels of at least one sugar in developing seeds in a plant, with the methods comprising inserting an exogenous nucleic acid, which codes for at least one sugar transporter protein (SWEET protein), into a plant cell to create a transgenic plant cell, and subjecting the transgenic plant cell to conditions that promote expression of the at least one SWEET protein during seed development. The methods results in transgenic plant seeds, and transgenic plants that produce seed, where the levels of at least one sugar are increased as compared to seeds from non-transgenic plants of the same species grown under the same conditions.

Abstract: The invention relates to engineered transporter proteins comprising at least one fluorescent reporter covalently bound to the transporter protein, wherein the transporter proteins of the present invention comprise a structural inverted repeat motif, with the motif comprising a first and second subunit that are structural inverted repeats of one another and that are joined to one another by a polypeptide loop.

Abstract: The disclosure relates to engineered transport proteins comprising at last one fluorescent reporter covalently bound to the transporter protein, wherein the transporter proteins comprise a structural inverted repeat motif, with the motif comprising a first and second subunit that are structural inverted repeats of one another and that are joined to one another by a polypeptide loop.

Abstract: The invention provides fusion proteins comprising at least one fluorescent protein that is linked to at least one transporter protein that changes three-dimensional conformation upon specifically transporting its substrate. The transporter protein may be a nitrate transporter, a peptide transporter, or a hormone transporter. The invention provides fusion proteins comprising at least one fluorescent protein that is linked to at least one mechanosensitive ion channel protein. The invention also provides for methods of using the fusion proteins of the present invention and nucleic acids encoding the fusion proteins.

Abstract: A nanosensor for detecting and quantifying lactate in different types of samples, such as tissues, intra-cellular and subcellular compartments, with high spatial and temporal resolution is disclosed. Methods comprising use of the nanosensor for quantifying the activity of lactate transporters, rates of cellular lactate production and cellular lactate consumption, and rate of mitochondrial pyruvate consumption are also disclosed. Methods for quantifying the transformation in energy metabolism that characterizes cancer cells with single-cell resolution and for detecting interference of candidate drugs with mitochondrial energetics are additionally disclosed.

Abstract: The present invention relates to genetically modified plant cells that have reduced expression or activity of at least one amino acid efflux transporter and/or at least one mineral efflux transporter compared to levels of expression or activity of the at least one amino acid efflux transporter or mineral efflux transporter in an unmodified plant cell. The present invention also relates to genetically modified plant cells that have increased expression or activity of at least one amino acid influx transporter and/or at least one mineral influx transporter compared to levels of expression or activity of the at least one amino acid influx transporter or mineral influx transporter in an unmodified plant cell.

Abstract: The present invention relates to genetically modified plant cells that have altered expression or activity of at least one sucrose efflux transporter compared to levels of expression or activity of the at least one sucrose efflux transporter in an unmodified plant cell.

Abstract: The disclosure relates to engineered transport proteins comprising at last one fluorescent reporter covalently bound to the transporter protein, wherein the transporter proteins comprise a structural inverted repeat motif, with the motif comprising a first and second subunit that are structural inverted repeats of one another and that are joined to one another by a polypeptide loop.

Abstract: Intramolecular biosensors are disclosed, including PBP-based biosensors, comprising a ligand binding domain fused to donor and fluorescent moieties that permit detection and measurement of Fluorescence Resonance Energy Transfer upon binding ligand. At least one of the donor and fluorescent moieties may be internally fused to the biosensor such that both ends of the internally fused fluorophore are fixed. In addition, methods of improving the sensitivity of terminally fused biosensors are provided. The biosensors of the invention are useful for the detection and quantification of ligands in vivo and in culture.

Abstract: Phosphate biosensors are disclosed, which comprise a phosphate binding domain conjugated to donor and fluorescent moieties that permit detection and measurement of Fluorescence Resonance Energy Transfer upon phosphate binding. Such biosensors are useful for real time monitoring of phosphate metabolism in living cells.

Abstract: The invention provides fusion proteins comprising at least two fluorescent proteins, with the fluorescent proteins emitting different wavelengths of light from one another, at least one plant hormone binding domain that changes three-dimensional conformation upon specifically binding to a plant hormone, and two linker peptides, with the first linker linking the first fluorescent protein to the N-terminus of the plant hormone binding domain and the second linker linking the second fluorescent protein to the C-terminus of the plant hormone binding domain. The invention also provides for methods of using the fusion proteins of the present invention and nucleic acids encoding the fusion proteins.

Abstract: Intramolecular biosensors are disclosed, including PBP-based biosensors, comprising a ligand binding domain fused to donor and fluorescent moieties that permit detection and measurement of Fluorescence Resonance Energy Transfer upon binding ligand. At least one of the donor and fluorescent moieties may be internally fused to the biosensor such that both ends of the internally fused fluorophore are fixed. In addition, methods of improving the sensitivity of terminally fused biosensors are provided. The biosensors of the invention are useful for the detection and quantification of ligands in vivo and in culture.

Abstract: Environmentally stable biosensors are disclosed, which comprise a ligand binding domain from a thermophilic organism conjugated to donor and fluorescent moieties that permit detection and measurement of Fluorescence Resonance Energy Transfer upon ligand binding. Such biosensors demonstrate enhanced acid-, thermal- and chemical stability as compared to sensors constructed using protein domains from mesophilic organisms.

Abstract: Neurotransmitter biosensors are disclosed, including YbeJ-based glutamate binding biosensors, comprising a neurotransmitter binding domain conjugated to donor and fluorescent moieties that permit detection and measurement of Fluorescence Resonance Energy Transfer upon binding neurotransmitter. Such biosensors are useful for the detection of neurotransmitter concentrations in vivo and in culture.