title: PICK1 regulates the trafficking of ASIC1a and acidotoxicity in a BAR domain lipid binding-dependent manner.
abstract: BACKGROUND
  Acid-sensing ion channel 1a (ASIC1a) is the major ASIC subunit determining acid-activated currents in brain neurons. Recent studies show that ASIC1a play critical roles in acid-induced cell toxicity. While these studies raise the importance of ASIC1a in diseases, mechanisms for ASIC1a trafficking are not well understood. Interestingly, ASIC1a interacts with PICK1 (protein interacting with C-kinase 1), an intracellular protein that regulates trafficking of several membrane proteins. However, whether PICK1 regulates ASIC1a surface expression remains unknown.
  
  
  RESULTS
  Here, we show that PICK1 overexpression increases ASIC1a surface level. A BAR domain mutant of PICK1, which impairs its lipid binding capability, blocks this increase. Lipid binding of PICK1 is also required for PICK1-induced clustering of ASIC1a. Consistent with the effect on ASIC1a surface levels, PICK1 increases ASIC1a-mediated acidotoxicity and this effect requires both the PDZ and BAR domains of PICK1.
  
  
  CONCLUSIONS
  Taken together, our results indicate that PICK1 regulates trafficking and function of ASIC1a in a lipid binding-dependent manner.
authors.affiliation: Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
authors.forename: Wenying
authors.initials: W
authors.lastname: Jin
authors.forename: Chong
authors.initials: C
authors.lastname: Shen
authors.forename: Lan
authors.initials: L
authors.lastname: Jing
authors.forename: Xiang-ming
authors.initials: XM
authors.lastname: Zha
authors.forename: Jun
authors.initials: J
authors.lastname: Xia
mesh_terms: D062565:Acid Sensing Ion Channels; D000818:Animals; D019556:COS Cells; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002522:Chlorocebus aethiops; D003598:Cytoskeletal Proteins; D057809:HEK293 Cells; D006801:Humans; D006863:Hydrogen-Ion Concentration; D050356:Lipid Metabolism; D051379:Mice; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D015222:Sodium Channels / Q000235:genetics / Q000378:metabolism*
chemical_list: C568266:ASIC1 protein, human; C568267:ASIC1 protein, mouse; D062565:Acid Sensing Ion Channels; D002352:Carrier Proteins; D003598:Cytoskeletal Proteins; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; C498298:PICK1 protein, rat; D011993:Recombinant Fusion Proteins; D015222:Sodium Channels