Posh nucleic acids, polypeptides and related methods

Abstract

The application discloses novel polypeptides and nucleic acids involved in a variety of biological processes, including viral reproduction. Related methods and compositions are also described.

1 . A method of inhibiting viral maturation in a subject in need thereof comprising administering to the subject an agent that inhibits a ubiquitin-related activity of a POSH polypeptide. 
     
     
         2 . The method of  claim 1 , wherein the POSH polypeptide is selected from the group consisting of SEQ ID NOS: 2, 5, 7, 9 and 11 and fragments comprising at least 20 consecutive amino acids of any of SEQ ID NOS: 2, 5, 7, 9, and 11. 
     
     
         3 . The method of  claim 1 , comprising inhibiting an activity of the RING domain of the POSH polypeptide. 
     
     
         4 . The method of  claim 1 , wherein the ubiquitin-related activity is selected from the group consisting of self-ubiquitination of the POSH polypeptide and ubiquitination of a target protein. 
     
     
         5 . The method of  claim 1 , wherein the agent is selected from the group consisting of a small molecule, an antibody, a peptidomimetic, and a polypeptide. 
     
     
         6 . The method of  claim 5 , wherein the agent is an antibody or a fragment thereof, specifically immunoreactive with an epitope of SEQ ID NO: 30. 
     
     
         7 . The method of  claim 1 , wherein the agent is selected from the group consisting of an antisense oligonucleotide, an RNAi construct, a DNA enzyme, and a ribozyme. 
     
     
         8 . The method of  claim 7 , wherein the RNAi construct is selected from the group consisting of any one of SEQ ID NOS: 15, 18, 18, 19, 21, 22, 24, and 25. 
     
     
         9 . The method of  claim 1 , comprising inhibiting viral maturation of a virus selected from the group consisting of an envelope virus, retroid virus or a RNA virus. 
     
     
         10 . The method of  claim 9 , wherein
 a) the retroid virus is a lentivirus;   b) the retroid virus is an HIV1 lentivirus;   c) the RNA virus is a Hepatitis C virus;   d) the RNA virus is a filovirus; or   e) the RNA virus is an ebola filovirus.   
     
     
         11 . The method of  claim 1 , comprising inhibiting viral maturation of a Hepatitis B virus. 
     
     
         12 . The method of  claim 1 , wherein the agent is formulated for topical administration. 
     
     
         13 . The method of  claim 1 , wherein the agent is formulated as an inhalant. 
     
     
         14 . The method of  claim 1 , wherein the agent inhibits POSH-mediated viral release. 
     
     
         15 . The method of  claim 14 , wherein the agent inhibits a POSH-mediated viral release polypeptide. 
     
     
         16 . The method of  claim 15 , wherein the POSH-mediated viral release polypeptide is selected from the group consisting of POSH, POSH-multimers, a nucleic acid encoding polypeptide comprising a RING domain and a SH3 domain, Brca1, Bard1, Nef, Rac, Rac1, PAK1, PAK2, PAK family, Vav, Cdc42, PI3K, Nedd4, src, src family polypeptides, gag, tsg101, VASP, RNB6, WASP, N-WASP, KIAA0674. 
     
     
         17 . The method of  claim 14 , comprising inhibiting viral release of a virus selected from the group consisting of an envelope virus, a retroid virus or a RNA virus. 
     
     
         18 . The method of  claim 17 , wherein
 a) the retroid virus is a lentivirus;   b) the retroid virus is an HIV1 lentivirus;   c) the RNA virus is a Hepatitis C virus;   d) the RNA virus is a filovirus; or   e) the RNA virus is an ebola filovirus.   
     
     
         19 . The method of  claim 14 , comprising inhibiting viral release of a Hepatitis B virus. 
     
     
         20 . A method for identifying an antiviral agent, comprising:
 a) providing a POSH polypeptide and a test agent; and   b) identifying a test agent that interacts with the POSH polypeptide.   
     
     
         21 . A method for testing a ubiquitin-related activity of a POSH (Plenty Of SH3 domains) polypeptide comprising:
 forming a mixture compatible with the ubiquitin-related activity comprising: a ubiquitin; a ubiquitin-conjugating enzyme (E2); and a POSH polypeptide; and   detecting whether said ubiquitin binds to said POSH polypeptide.   
     
     
         22 . The method of  claim 21 , wherein the POSH polypeptide is selected from the group consisting of SEQ ID NOS: 2, 5, 7, 9, 11, and 26 and fragments comprising at least 20 consecutive amino acids of any of SEQ ID NOS: 2, 5, 7, 9, and 11. 
     
     
         23 . The method of  claim 21 , wherein the ubiquitin is detectably labeled. 
     
     
         24 . The method of  claim 21 , wherein the POSH polypeptide is detectably labeled. 
     
     
         25 . The method of  claim 23  or  24 , wherein said label is selected from the group consisting of a radioisotopes, fluorescent compounds, enzymes, and enzyme co-factors. 
     
     
         26 . The method of  claim 21 , wherein the ubiquitin is provided in a form selected from the group consisting of:
 an unconjugated ubiquitin, in which case the mixture further comprises an E1 and adenosine triphosphate;   an activated E1:ubiquitin conjugate; and   an activated E2:ubiquitin thioester complex.   
     
     
         27 . The method of  claim 21 , wherein the POSH polypeptide has ubiquitin ligase activity and comprises a sequence selected from the group consisting of (a) SEQ ID NO: 26 and (b) a sequence that is at least 95% identical to SEQ ID NO: 26. 
     
     
         28 . The method of  claim 21 , wherein the mixture additionally comprises a ubiquitin-activating enzyme (E1). 
     
     
         29 . The method of  claim 21 , wherein the mixture additionally comprises a test agent. 
     
     
         30 . The method of  claim 29 , wherein the test agent alters the binding of said ubiquitin to said POSH polypeptide.