A Kinase Anchoring Protein 9 Is a Novel Myosin VI Binding Partner That Links Myosin VI with the PKA Pathway in Myogenic Cells

Figure 3

AKAP9 and MVI colocalization in undifferentiated myoblasts and in myotubes by means of confocal microscopy. (a) Untreated C2C12 myoblasts (C2C12), (b) scrambled cells, (c) MVI-depleted cells (MVI-KD), and (d) day 7 myotubes. (e) MVI-KD cells expressing GFP-MVI and (f) MVI-KD cells expressing GFP-tagged MVI globular tail domain (GFP-MVI-GT). MVI in (a)–(d) was visualized with anti-MVI antibody (in green) and in (e)-(f) by the GFP fluorescence and AKAP9 with anti-AKAP9 antibody (in red) and nuclei (in (d)) with ToPro3 (in blue). Insets, 2-3x magnification of the areas marked in the merged panels. (a′) AKAP9 (stained with anti-AKAP9 antibody, in red) and MVI (stained with anti-MVI antibody in blue) were associated with early endosomes containing overexpressed Rab5-GFP (in green). Images of the central cell section (z = 0.3μm) were obtained with a Leica confocal microscope. Bars: in (a)–(f), 20μm and in (a′), 2μm.