Figure 2.
Expression of myopodin in skeletal, heart, and smooth muscle cells. (a) A single 3.6 kB mRNA is detected in mouse skeletal muscle (S) and heart (H). The expression in the heart is weaker than in skeletal muscle. (b) Western blot analysis of myopodin and synaptopodin in cytosolic extracts of mouse skeletal (S) and heart (H) muscle. A 110-kD band corresponding to synaptopodin is found in both tissues using antisynaptopodin antibody NT. The myopodin antibody SRIB1 reveals a band of 80-kD in skeletal muscle and ∼95 kD in the heart (Fig. 2 b). Both signals were blocked with the corresponding peptide showing the specificity of the bands. Identical results were obtained for SRIB2 (Fig. 2 b). (c) Western blot analysis of myopodin (left) in colon (C), stomach (St), uterus (U), and lung (Lu) shows a single 80-kD band in all lanes. Interestingly the same tissues also express synaptopodin (right, arrow). (d) Immunofluorescence microscopy of myopodin in mouse kidney, colon, stomach, and uterus. In the kidney, myopodin is strongly expressed in arteriolar smooth muscle cells (arrowhead), but not in glomerular (G) podocytes. In colon, stomach, and uterus myopodin expression is restricted to smooth muscle cells. In the colon, the arrowheads mark the muscularis mucosae. Bars: (kidney) 40 μm; (stomach, colon, and uterus) 300 μm.