Dyneins are a group of microtubule-activated ATPases that serve to convert chemical energy into mechanical energy. Cytoplasmic dynein has been implicated in a variety of other forms of intracellular motility, including retrograde axonal transport, protein sorting between apical and basolateral surfaces, and redistribution of organelles like endosomes and lysosomes. The predicted partial protein sequence shares 99% and 34% identity with rat DHC1a and human DNHC2, respectively. Antibodies against DHC1 recognized a high molecular mass protein on Western blots of extracts from several mammalian cell lines. Northern blot analysis revealed that DHC1 is expressed as an approximately 15-kb mRNA in several mammalian cells lines and human tissues, including those that make neither cilia nor flagella.