The heteromultimeric association of Kv1.2, Kv1.4, and Kv1.5 α subunits in cultured Schwann cells. A, Coimmunoprecipitation of Kv1.5 with other Shaker-like subunits. SC membranal fractions were subjected to immunoprecipitation with anti-Kv2.1, anti-Kv1.2, anti-Kv1.4, or anti-Kv1.5 antibodies, and blots were probed with anti-Kv1.5 antibodies. To verify the presence of channel proteins, blots were stripped and reprobed with the respective anti-Kv antibodies (data not shown). Nonspecific bands corresponding to immunoglobulin heavy chain (IgG) are also observed.B, Reciprocal coimmunoprecipitation of Kv1.2 and Kv1.4 with Kv1.5. Left, SC membrane proteins were immunoprecipitated with either Kv1.5, Kv2.1, or Kv3.1 antibodies, and blots were probed with anti-Kv1.2. Right, SC membrane proteins were immunoprecipitated with either Kv1.4, Kv1.5, or preimmune antibodies (P.I.), and blots were probed with anti-Kv1.4. An aliquot of SC membranes corresponding to ∼10% of the proteins used in immunoprecipitation (SC input) was used as positive control. C, SCs were double labeled with mouse monoclonal anti-Kv1.5 (C1, C3) and rabbit polyclonal anti-Kv1.2 (C2,C4). Indirect immunofluorescence with anti-mouse FITC and anti-rabbit TRITC was used for detection. Scale bar:C1–C2, 35 μm; C3–C4, 17 μm.