A method of precipitating cell membrane fragments from a cell lysate is disclosed. The method comprises contacting the cell lysate with a hydrophobic chelator and a metal ion under conditions that allow precipitation of the cell membrane fragments. Kits for precipitating cell membrane fragments are also disclosed.

Compositions and methods for altering cell activity and function by expressing a light-activated ion pump polypeptide in a cell and contacting the cell with light that activates the expressed light-activated ion pump polypeptide. In some aspects of the invention, a light-activated ion pump polypeptide is a modified haloarcula halorhodopsin polypeptide, for example, a modified Halo 57 polypeptide.

Compositions and methods for altering cell activity and function by expressing a light-activated ion pump polypeptide in a cell and contacting the cell with light that activates the expressed light-activated ion pump polypeptide. In some aspects of the invention, a light-activated ion pump polypeptide is a modified haloarcula halorhodopsin polypeptide, for example, a modified Halo 57 polypeptide.

Stimulation of target cells using light, e.g., in vivo, is implemented using a variety of methods and devices. In one example, embodiments involve methods for stimulating target cells using a photosensitive protein that allows the target cells to be stimulated in response to light. In another specific example embodiment, target cells are stimulated using an implantable arrangement. The arrangement includes an electrical light-generation means for generating light and a biological portion. The biological portion has a photosensitive bio-molecular arrangement that responds to the generated light by stimulating target cells in vivo. Other aspects and embodiments are directed to systems and methods for screening chemicals based screening chemicals to identify their effects on cell membrane ion channels and pumps, and to systems and methods for controlling an action potential of neuron (e.g., in in vivo and in vitro environments).

A method of precipitating cell membrane fragments from a cell lysate is disclosed. The method comprises contacting the cell lysate with a hydrophobic chelator and a metal ion under conditions that allow precipitation of the cell membrane fragments. Kits for precipitating cell membrane fragments are also disclosed.

A method of precipitating cell membrane fragments from a cell lysate is disclosed. The method comprises contacting the cell lysate with a hydrophobic chelator and a metal ion under conditions that allow precipitation of the cell membrane fragments. Kits for precipitating cell membrane fragments are also disclosed.

The present invention relates to the use of an isolated nucleic acid molecule comprising a nucleotide sequence coding for a hyperpolarizing light-gated ion channel or pump gene from an archeon or for a light-active fragment of said gene, or the nucleotide sequence complementary to said nucleotide sequence, for treating or ameliorating blindness. The light-gated ion channel or pump gene can be a halorhodopsin gene.

The present invention relates to the use of an isolated nucleic acid molecule comprising a nucleotide sequence coding for a hyperpolarizing light-gated ion channel or pump gene from an archeon or for a light-active fragment of said gene, or the nucleotide sequence complementary to said nucleotide sequence, for treating or ameliorating blindness. The light-gated ion channel or pump gene can be a halorhodopsin gene.

Stimulation of target cells using light, e.g., in vitro, is implemented using a variety of methods and devices. One example involves a vector for delivering a light-activated NpHR-based molecule comprising a nucleic acid sequence that codes for light-activated NpHR-based molecule and a promoter. Either a high expression of the molecule manifests a toxicity level that is less than about 75%, or the light-activated NpHR-based proteins are expressed using at least two NpHR-based molecular variants. Each of the variants characterized in being useful for expressing a light-activated NpHR-based molecule that responds to light by producing an inhibitory current to dissuade depolarization of the neuron. Other aspects and embodiments are directed to systems, methods, kits, compositions of matter and molecules for ion pumps or for controlling inhibitory currents in a cell (e.g., in in vivo and in vitro environments).

Stimulation of target cells using light, e.g., in vitro, is implemented using a variety of methods and devices. One example involves a vector for delivering a light-activated NpHR-based molecule comprising a nucleic acid sequence that codes for light-activated NpHR-based molecule and a promoter. Either a high expression of the molecule manifests a toxicity level that is less than about 75%, or the light-activated NpHR-based proteins are expressed using at least two NpHR-based molecular variants. Each of the variants characterized in being useful for expressing a light-activated NpHR-based molecule that responds to light by producing an inhibitory current to dissuade depolarization of the neuron. Other aspects and embodiments are directed to systems, methods, kits, compositions of matter and molecules for ion pumps or for controlling inhibitory currents in a cell (e.g., in in vivo and in vitro environments).