Fig. 4. Myo5c protein is abundant in epithelial and secretory tissue. (A) Immunoblot showing the protein distribution of class V myosins in mouse tissues. Myo5a is abundant in brain, whereas Myo5b and Myo5c are more widely distributed in non-neuronal tissues. Gels were run in triplicate, samples were loaded equally by wet tissue weight and blots were probed with antibodies to Myo5a, Myo5b or Myo5c. It is unclear if the lower band detected by the Myo5b antibodies in brain represents a breakdown product. (B) Immunoblot showing that Myo5c is enriched in the mucosa of mouse colon, but not the underlying muscle wall. The Ponceau stain of this blot shows that myosin-II and actin are found primarily with the muscle wall. The mucosa was dissected from 0.4 g of colon by scraping. The mucosal layer and the muscle wall were then separately homogenized in 4 ml of buffer as for the other mouse tissue homogenates, and equal volumes were loaded. (C) Immunblots of untransfected and transfected Hela cells. Blotting of HeLa cell lysates reveals that these cells endogenously express both Myo5a and Myo5c (left panels, 50 µg load). HeLa cells transfected with the GFP-Myo5c tail express a protein of the expected size, 120 kDa (right panels, 20 µg load).