Immunoblot analysis of NOS protein expression in subcellular fractions from HMC-1 cells. HMC-1 cells were lysed and separated into cytosolic (Cy) or nuclear (N) fractions as described in “Materials and methods”; proteins from each fraction were separated by SDS-PAGE under reducing conditions. Control (Con) proteins (human brain and endothelial cell lysate, respectively) were run concurrently. Representative immunoblot of nNOS and eNOS content in subcellular fractions. For all blots, equal amounts of protein (15 μg) were loaded. Molecular weight markers indicated at right. All blots are representative of at least 3 independent experiments.