Figure 6.

Cell migration is required for proper midbody localization of Crk and syntaxin-2 but not paxillin. Subconfluent HeLa cells were treated with MAB17781 or IgG control antibody, fixed and stained for citron K (red), Hoechst nuclear dye (blue) and either pY118-paxillin (green) in (A) or Crk (green), which interacts with both isoforms of Crk, in (C). In (E) HeLa cells were stained with Hoechst nuclear dye (blue), β-tubulin (red) and syntaxin-2 (green). The fraction of cells with paxillin (B), Crk (D) or syntaxin-2 (E) at the midbody were tabulated from multiple fields by IF microscopy. Localization of Crk and syntaxin-2 but not paxillin to the midbody was significantly inhibited (p < 0.01, χ² test) in MAB17781-treated cells. The numbers above the column indicate the total number of cells analyzed. Note that Crk appears as aggregates near citron K at the midbody in (C). Also of note, the syntaxin-2 part in MAB17781-treated cells (E) is overexposed to show the absence of this protein at the midbody more clearly.