Blue light-activated ion channel molecules and uses thereof

Abstract

The invention, in some aspects relates to light-activated ion channel polypeptides and encoding nucleic acids and also relates in part to compositions comprising light-activated ion channel polypeptides and methods using light-activated ion channel polypeptides to alter cell activity and function.

What is claimed is: 
     
         1 . A light-activated ion channel polypeptide, wherein the ion channel when expressed in a membrane and contacted with blue light is activated, the polypeptide comprises a wild-type or modified  Scherffelia  channelrhodopsin polypeptide sequence, and wherein the light-activated ion channel polypeptide is not present in a  Scherffelia  cell. 
     
     
         2 - 5 . (canceled) 
     
     
         6 . The light-activated ion channel polypeptide of  claim 1 , wherein the polypeptide comprises the amino acid sequence of ChR64 (SEQ ID NO:2). 
     
     
         7 . The light-activated ion channel polypeptide of  claim 1 , wherein the modified  Scherffelia  channelrhodopsin polypeptide sequence comprises a E→A substitution at an amino acid residue corresponding to amino acid 154 of the amino acid sequence of ChR64 (SEQ ID NO:2). 
     
     
         8 . The light-activated ion channel polypeptide of  claim 1 , wherein the modified  Scherffelia  channelrhodopsin polypeptide sequence is the sequence set forth as SEQ ID NO:7. 
     
     
         9 - 10 . (canceled) 
     
     
         11 . A cell comprising the light-activated ion channel polypeptide of  claim 1 , wherein the cell is one or more of: (i) an excitable cell and (ii) a mammalian cell. 
     
     
         12 - 17 . (canceled) 
     
     
         18 . A nucleic acid molecule comprising the sequence encoding the light-activated ion channel polypeptide of  claim 1 , wherein the nucleic acid molecule is not in a  Scherffelia  cell. 
     
     
         19 - 21 . (canceled) 
     
     
         22 . A vector comprising the nucleic acid sequence of  claim 18 . 
     
     
         23 - 29 . (canceled) 
     
     
         30 . A method of depolarizing a cell, the method comprising,
 contacting a cell with a blue light under conditions suitable to depolarize the cell, wherein (i) the cell comprises a light-activated ion channel polypeptide that is activated when contacted with blue light, (ii) the light-activated ion channel polypeptide comprises a wild-type or modified  Scherffelia  channelrhodopsin polypeptide sequence, and (iii) the cell is not a  Scherffelia  cell; and depolarizing the cell.   
     
     
         31 - 32 . (canceled) 
     
     
         33 . The method of  claim 30 , wherein the amino acid sequence of the light-activated ion channel polypeptide sequence comprises the sequence set forth as SEQ ID NO:2 or SEQ ID NO:7. 
     
     
         34 - 35 . (canceled) 
     
     
         36 . The method of  claim 30 , wherein the cell is a mammalian cell. 
     
     
         37 - 38 . (canceled) 
     
     
         39 . The method of  claim 30 , wherein the cell is in a subject and depolarizing the cell diagnoses or assists in a diagnosis of a disorder in the subject. 
     
     
         40 . The method of  claim 30 , wherein the cell is in a subject and depolarizing the cell treats a disorder in the subject. 
     
     
         41 . A method of assessing the effect of a candidate compound on a cell, the method comprising,
 a) contacting a test cell comprising a light-activated ion channel polypeptide that is activated when contacted with blue light, wherein the ion channel polypeptide comprises a wild-type or modified  Scherffelia  channelrhodopsin polypeptide sequence and the cell is not a  Scherifelia  cell, with blue light under conditions suitable for depolarization of the cell;   b) contacting the test cell with a candidate compound; and   c) identifying the presence or absence of a change in depolarization or a change in a depolarization-mediated cell characteristic in the test cell contacted with the blue light and the candidate compound compared to depolarization or the depolarization-mediated cell characteristic, respectively, in a control cell contacted with the blue light and not contacted with the candidate compound;   wherein a change in depolarization or the depolarization-mediated cell characteristic in the test cell compared to the control cell indicates an effect of the candidate compound on the test cell.   
     
     
         42 - 46 . (canceled) 
     
     
         47 . The method of  claim 41 , wherein the amino acid sequence of the light-activated ion channel polypeptide comprises an amino acid sequence forth as SEQ ID NO:2 or SEQ ID NO:7. 
     
     
         48 - 51 . (canceled) 
     
     
         52 . The method of  claim 41 , wherein the cell is a mammalian cell. 
     
     
         53 - 54 . (canceled) 
     
     
         55 . A method of treating a disorder in a subject, the method comprising
 a) administering to a subject in need of such treatment, a therapeutically effective amount of a light-activated ion channel polypeptide that is activated when contacted with blue light, wherein the ion channel polypeptide comprises a wild-type or modified  Scherffelia  channelrhodopsin polypeptide sequence, to treat the disorder and   b) contacting the cell with blue light and activating the light-activated ion channel in the cell under conditions sufficient to depolarize the cell, wherein depolarizing the cell treats the disorder in the subject.   
     
     
         56 - 65 . (canceled) 
     
     
         66 . The method of  claim 55 , wherein the amino acid sequence of the blue-light-activated ion channel is set forth as SEQ ID NO:2 or SEQ ID NO:7. 
     
     
         67 - 71 . (canceled) 
     
     
         72 . A fusion protein comprising the light-activated ion channel polypeptide of  claim 1 . 
     
     
         73 . The light-activated ion channel polypeptide of  claim 1 , wherein amino acid sequence of the modified  Scherffelia  channelrhodopsin polypeptide, when aligned with the polypeptide set forth as SEQ ID NO: 2 has one or more of at least 75%, 80%, 85%, 90%, and 95% sequence identity to the corresponding amino acids of SEQ ID NO:2. 
     
     
         74 . The light-activated ion channel polypeptide of  claim 30 , wherein amino acid sequence of the modified  Scherffelia  channelrhodopsin polypeptide, when aligned with the polypeptide set forth as SEQ ID NO: 2 has one or more of at least 75%, 80%, 85%, 90%, and 95% sequence identity to the corresponding amino acids of SEQ ID NO:2.