10 nm filaments in normal and transformed cells.

An antibody was raised against an electrophoretically homogeneous protein from cultured fibroblasts and shown to be directed against 10 nm filaments. The antiserum did not stain microtubules or actin microfilaments. The distribution of 10 nm filaments in normal cells was studied during growth, spreading, locomotion, mitosis, and after treatment with colchicine and cytochalasin B. The 58,000 dalton subunit protein is apparently all polymerized in the filaments which are insoluble in nonionic detergent. The distribution of 10 nm filaments is altered by colchicine treatments which disrupt microtubules. The organization of 10 nm filaments is altered in transformed cells.