MYO3β is a member of the Class III myosins that are actin-dependent motor proteins containing an amino-terminal kinase domain. MYO3β contains an N-terminal kinase domain, followed by motor, neck, and tail domains. The MYO3β gene generates a variety of splice variants that contain 1 or 2 calmodulin-binding (IQ) motifs in the neck domain and 1 of 3 domains in the tail domain. Northern blot analysis shows expression of a 7-kb MYO3β transcript in the human retina but not in a RPE cell line (1). The MYO3β gene transcript is also detected in the kidney, intestine and testis. The MYO3β gene maps to chromosome 2q31.1-q31.2 by genomic sequence alignment.