Fig. 2. Distinct forms of mammalian CHMP1 protein are found in cytoplasmic and nuclear compartments. (A) The subcellular distribution of CHMP1 was determined by western blot analysis with purified anti-CHMP1 antiserum after 18% SDS-PAGE. (B) Human cells lines derived from cervical (HeLa), prostate (LNCaP), breast (MCF7), colon (HT-29), and chorionic (JAR) carcinomas were compared with primary human umbilical vein endothelial cells (HUV-EC-C) for CHMP1 expression levels and subcellular distribution. (C) Expression levels of the nuclear and cytoplasmic forms of CHMP1 are compared in a mouse cell line (C2C12), mouse embryo fibroblasts and the indicated adult mouse tissues. Tissue extracts are unfractionated and represent total protein. Blots were stripped and re-probed with antibody to alpha-tubulin (cytoplasm-specific) and matrin 4 (nuclear matrix-specific) to demonstrate the accuracy of the fractionation. * indicates a nonspecific band. c, cytoplasm; ds, nuclear proteins released by DNaseI-digestion plus 800 mM NaCl-extraction; m, nuclear matrix solubilized by detergent; w, whole cell with complete detergent solubilization (see Materials and Methods).