Photorelease of Carboxylic Acids from 1-Acyl-7-nitroindolines in Aqueous Solution:  Rapid and Efficient Photorelease of <scp>l</scp>-Glutamate<sup>1</sup>

Papageorgiou, George; Ogden, David; Barth, Andreas; Corrie, John E. T.

doi:10.1021/ja990931e

Cited by 137 publications

(121 citation statements)

References 21 publications

(17 reference statements)

Supporting

Mentioning

116

Contrasting

Unclassified

Order By: Relevance

“…Together, these data indicate that MNI-alanine is not transported by these three amino acid transporters at the concentrations tested. Furthermore, the results suggest that the background concentration of free alanine in the caged compound is very low, as expected from previous data on the stability of nitroindoline-caged compounds (30).…”

Section: Characterization Of Biological Properties Of Mni-alanine Witsupporting

confidence: 87%

Pre-steady-State Currents in Neutral Amino Acid Transporters Induced by Photolysis of a New Caged Alanine Derivative

et al. 2007

Self Cite

View full text Add to dashboard Cite

Na + -dependent transmembrane transport of the small neutral amino acids, such as glutamine and alanine, is mediated, among others, by the neutral amino acid transporters of the solute carrier 1 (SLC1, ASCT1 and 2) and SLC38 families (SNAT1, 2 and 4). Many mechanistic aspects of amino acid transport by these systems are not well understood. Here, we describe a new photolabile alanine derivative, based on protection of alanine with the 4-methoxy-7-nitroindolinyl (MNI) caging group, which we use for pre-steady-state kinetic analysis of alanine transport by ASCT2 and SNAT1 and 2. MNI-alanine has favorable photochemical properties and is stable in aqueous solution. It is also inert with respect to the transport systems studied. Photolytic release of free alanine results in the generation of significant transient current components in HEK293 cells expressing the ASCT2, SNAT1 and SNAT2 proteins. In ASCT2, these currents show biphasic decay with time constants, τ, in the 1-30 ms time range. They are fully inhibited in the absence of extracellular Na + , demonstrating that Na + binding to the transporter is necessary for induction of the alanine-mediated current. For SNAT1, these transient currents differ in their time course (τ = 1.6 ms) from previously described pre-steady-state currents generated by applying steps in the membrane potential (τ ~ 4-5 ms), indicating that they are associated with a fast, previously undetected, electrogenic partial reaction in the SNAT1 transport cycle. The implications of these results for the mechanisms of transmembrane transport of alanine are discussed. The new caged alanine derivative will provide a useful tool for future, more detailed studies of neutral amino acid transport.Neutral amino acids are transported across cell membranes by a variety of transport systems [reviewed in (1)]. Some of these systems, which actively transport neutral amino acids against a concentration gradient, are powered by cotransport of Na + down its own transmembrane concentration gradient. For small neutral amino acids these systems include System N, System A, and System ASC. System N and System A belong to the same solute carrier (SLC) protein family (SLC38) and the known cloned members of this family have collectively been termed sodium-coupled neutral amino acid transporters (SNAT) (2). Members 1, 2 and 4 of this family are thought to belong to the System A class (3,4), whereas members 3 and 5 belong to the System N class (5,6). In contrast, System ASC transporters belong to the SLC1 family of transport proteins and the cloned members ASCT1 and ASCT2 have a high degree of sequence similarity with glutamate transporters (7-9). † This work was supported by a grant by the Florida Department of Health (04NIR-07) awarded to CG. Pre-steady-state kinetic techniques have been used in the past to study details of the transport mechanism of ion pumps (10,11) and secondary transporters (12)(13)(14). One means to obtain pre-steady-state kinetic data is to disturb an existing transporter steady state by a...

show abstract

Section: Characterization Of Biological Properties Of Mni-alanine Witsupporting

confidence: 87%

Pre-steady-State Currents in Neutral Amino Acid Transporters Induced by Photolysis of a New Caged Alanine Derivative

et al. 2007

Self Cite

View full text Add to dashboard Cite

show abstract

“…Caging the amine either directly or via the carbamate is the obvious solution to this crucial problem 63 , but these caged glutamates are uncaged too slowly to be useful 27 . Caging glutamate as an amide has provided a recent solution to this important dilemma 10 , 64 .…”

Section: Chemical Considerationsmentioning

confidence: 99%

Caged compounds: photorelease technology for control of cellular chemistry and physiology

2007

View full text Add to dashboard Cite

Caged compounds are light-sensitive probes that functionally encapsulate biomolecules in an inactive form. Irradiation liberates the trapped molecule, permitting targeted perturbation of a biological process. Uncaging technology and fluorescence microscopy are 'optically orthogonal': the former allows control, and the latter, observation of cellular function. Used in conjunction with other technologies (for example, patch clamp and/or genetics), the light beam becomes a uniquely powerful tool to stimulate a selected biological target in space or time. Here I describe important examples of widely used caged compounds, their design features and synthesis, as well as practical details of how to use them with living cells.The idea behind the caging technique is that a molecule of interest can be rendered biologically inert (or caged) by chemical modification with a photoremovable protecting group (Fig. 1). Illumination results in a concentration jump of the biologically active molecule that can bind to its cellular receptor, switching on (or off) the targeted process. Virtually every kind of signaling molecule or second messenger, of every size| [mdash]|from protons to proteins| [mdash]|has been caged 1 .Why are caged compounds so useful? A single component of cellular chemistry can control the function of a cell, and such cellular regulation can be temporally or spatially defined, intracellular or extracellular, and amplitude-or frequency-modulated 2 . Photomanipulation of cellular chemistry using caged compounds provides a uniquely powerful means to interact with such cellular dynamics, as it can touch upon any one of the above dimensions. Thus, since light passes through cell membranes, uncaging can rapidly release a biomolecule in an intracellular compartment. This space is not readily accessible to many second messengers (for example, inositol-1,4,5-trisphosphate (IP 3 ), ATP, Ca 2+ , cAMP, cGMP) when they are applied to cells externally, as their charge makes them impermeable to the plasma membrane. Furthermore, uniform illumination results in release throughout the cytosol, or the release can be localized by focusing the uncaging beam on one part of a cell. Likewise, extracellular uncaging of neurotransmitters and hormones is tunable, allowing stimulation of many neurons simultaneously or of single synapses| [mdash]|by global or focused illumination, respectively. Light cannot only be directed, but also modulated in time andCorrespondence should be addressed to Graham C R Ellis-Davies (cagedca@hotmail.com). (Fig. 2) has been widely used to study many Ca 2+ -controlled processes. In particular, secretory processes in neuronal and non-neuronal cells have been extensively studied with caged calcium 22 . Rapid uncaging of glutamate using two-photon photolysis is particularly useful for the rational stimulation of visually identified synapses in complex tissue preparations such as acutely isolated brain slices from the hippocampus 23 (Fig. 2b). Finally, uncaging of mRNA in vivo in zebrafish is an excellen...

show abstract

“…We thus activated inputs from layer 6 to layer 4 in a total of 12 neurons from first-order (SI: n ϭ 3; AI: n ϭ 3) and higher-order (SII: n ϭ 3; AII: n ϭ 3) areas. As an aid for identifying the precise location of layer 6 inputs, photostimulation with caged glutamate (Lam and Sherman 2007;Papageorgiou et al 1999;Shepherd et al 2003) was used in some experiments (n ϭ 8) to map the intracortical inputs to layer 4 (Fig. 7, A and B).…”

Section: Layer 6 To Layer 4 Synapsementioning

confidence: 99%

Synaptic Properties of Thalamic and Intracortical Inputs to Layer 4 of the First- and Higher-Order Cortical Areas in the Auditory and Somatosensory Systems

Lee

Sherman²

2008

Journal of Neurophysiology

151

186

View full text Add to dashboard Cite

Lee CC, Sherman SM. Synaptic properties of thalamic and intracortical inputs to layer 4 of the first-and higher-order cortical areas in the auditory and somatosensory systems. J Neurophysiol 100: 317-326, 2008. First published April 24, 2008 doi:10.1152/jn.90391.2008. The thalamus is an essential structure in the mammalian forebrain conveying information topographically from the sensory periphery to primary neocortical areas. Beyond this initial processing stage, "higherorder" thalamocortical connections have been presumed to serve only a modulatory role, or are otherwise functionally disregarded. Here we demonstrate that these "higher-order" thalamic nuclei share similar synaptic properties with the "first-order" thalamic nuclei. Using whole cell recordings from layer 4 neurons in thalamocortical slice preparations in the mouse somatosensory and auditory systems, we found that electrical stimulation in all thalamic nuclei elicited large, glutamatergic excitatory postsynaptic potentials (EPSPs) that depress in response to repetitive stimulation and that fail to activate a metabotropic glutamate response. In contrast, the intracortical inputs from layer 6 to layer 4 exhibit facilitating EPSPs. These data suggest that higher-order thalamocortical projections may serve a functional role similar to the first-order nuclei, whereas both are physiologically distinct from the intracortical layer 6 inputs. These results suggest an alternate route for information transfer between cortical areas via a corticothalamocortical pathway.

show abstract

Photorelease of Carboxylic Acids from 1-Acyl-7-nitroindolines in Aqueous Solution: Rapid and Efficient Photorelease of l-Glutamate¹

Cited by 137 publications

References 21 publications

Pre-steady-State Currents in Neutral Amino Acid Transporters Induced by Photolysis of a New Caged Alanine Derivative

Pre-steady-State Currents in Neutral Amino Acid Transporters Induced by Photolysis of a New Caged Alanine Derivative

Caged compounds: photorelease technology for control of cellular chemistry and physiology

Synaptic Properties of Thalamic and Intracortical Inputs to Layer 4 of the First- and Higher-Order Cortical Areas in the Auditory and Somatosensory Systems

Contact Info

Product

Resources

About

Photorelease of Carboxylic Acids from 1-Acyl-7-nitroindolines in Aqueous Solution: Rapid and Efficient Photorelease of l-Glutamate1

Cited by 137 publications

References 21 publications

Pre-steady-State Currents in Neutral Amino Acid Transporters Induced by Photolysis of a New Caged Alanine Derivative

Pre-steady-State Currents in Neutral Amino Acid Transporters Induced by Photolysis of a New Caged Alanine Derivative

Caged compounds: photorelease technology for control of cellular chemistry and physiology

Synaptic Properties of Thalamic and Intracortical Inputs to Layer 4 of the First- and Higher-Order Cortical Areas in the Auditory and Somatosensory Systems

Contact Info

Product

Resources

About

Photorelease of Carboxylic Acids from 1-Acyl-7-nitroindolines in Aqueous Solution: Rapid and Efficient Photorelease of l-Glutamate¹