The present invention discloses new muscle ring finger (MURF) proteins designate MURF-1, MURF-2 and MURF-3. The genes encoding these MURFs also are provided. MURFs interact with microtubules and thus play a role in cytoskeletal function, mitosis and cell growth. Thus, the uses of MURFs in diagnosis, treatment and drug screening, in particular relation to cardiomyopathies, are described.