Figure 1.

β-tubulin associates with KCNQ1. (A) KCNQ1 N-terminus (NtKCNQ1) and β-tubulin binding in yeast. Yeast cells were co-transformed with plasmid pairs coding for the indicated proteins fused to LexA BD or Gal4 AD. Transformants were plated on synthetic medium with or without histidine (His). Each patch represents an independent transformant. (B) Interaction of full-length KCNQ1 and β-tubulin. Left, COS-7 cells were transfected (+) or not (−) with a KCNQ1 coding vector. Cell extracts were incubated with anti-β-tubulin or anti-KCNQ1 antibody. The immunoprecipitated protein complexes were examined by immunoblotting with anti-KCNQ1 (left) or anti-β-tubulin (right) antibody. Right, Guinea pig heart extract was incubated with anti-KCNQ1 or anti-β-tubulin antibody (IP). The lysate and immunoprecipitated protein complexes were examined by immunoblotting with anti-KCNQ1 (top) or anti-β-tubulin (bottom) antibody. Control lane: the immunoprecipitation was performed with the corresponding antibody exhausted with the appropriate blocking peptide.