Expression of human KIF1Bα and interaction with KBP. A, lysates of 293 cells overexpressing KIF1Bα, KIF1Bα-myc and KIF1C or of untransfected 293 cells (10 fold amount of protein) were separated by SDS-PAGE, transferred to nitrocellulose and blotted with antiserum raised against the carboxyl-terminal part of KIF1Bα. B, affinity purified antibodies against KIF1Bα (top) and MitoTracker (middle) were used to stain NIH3T3 cells. The merged picture is shown at the bottom. Bar, 20 μm. C, KIF1Bα was immunoprecipitated from lysates of 293 cells overexpressing KBP-VSV either alone or together with KIF1Bα. Analysis was done as described and blotting performed with VSV monoclonal antibody. To confirm expression of the proteins, the filter was reprobed with KIF1Bα antibody, while KBP-VSV expression was detected in a separate aliquot of the cell lysates. D, untransfected BHK cells were lysed, proteins immunoprecipitated with the indicated antibodies against GST (control), KBP and KIF1Bα and analysed as before by blotting with anti-KIF1B antibody. Molecular mass markers are shown in kDa.