Loss of MYO1C causes age-dependent rod dysfunction in mice

In mice and human cell cultures, researchers examined how the motor protein MYO1C controls rhodopsin trafficking and retinal health. Biochemical tests and cell assays showed that the C-terminal domain of MYO1C binds rhodopsin to guide its membrane localization and ciliary targeting. In native mouse rod photoreceptors, MYO1C localized to both inner and outer segments. Mice with global Myo1c deficiency developed age-dependent rhodopsin mislocalization, apo-opsin accumulation, and progressive visual decline. This defect appeared at six months of age, marked by reduced scotopic electroretinogram responses and delayed a-wave recovery, while photopic responses remained largely intact. Targeted deletion in rod photoreceptors replicated this progressive scotopic loss, whereas cone-specific deletion left photopic visual function unaffected.