Mena/VASP expression in wild-type and MenaGT/GTVASP−/− mouse organs. Western blots to analyze Mena (A) and VASP (B) protein levels in heart, lung, brain, and spleen of wild-type (WT) and MenaGT/GTVASP−/− (dKO) mice. GAPDH and lysates of Mena- or VASP-transfected cells were used as controls. (A) The general Mena protein isoform (~80 kDa) is present in all analyzed organs, the neuronal splice variant (~140 kDa) is only detected in heart and brain. Whereas Mena protein in dKO brain is moderately reduced to ~30% of wild-type levels, Mena is almost undetectable in heart, lung, and spleen. The 130 kDa band seen in heart, lung, and brain likely represents a cross-reaction with an unrelated protein. (B) VASP (46 or 50 kDa, depending on phosphorylation state) expression is high in the neonatal heart and the adult lung and spleen, low in the adult heart, and nearly undetectable in the brain. No VASP protein is detected in dKO organs.