When I perform HeLa cell nucleus-cytoplasm seperation, I use human MSH2 as a marker protein for nucleus fraction. But the western blot show a sharp strong band in cytoplasm and nothing in nucleus. The antibody is bought from abcam (ab92473). Other marker proteins are all normal as predicted (HSP90 for cyto, HDAC1 for nuc). Could the antibody be mislabled? but the molecular weigh is correct.