May play a role in actin filament architecture in developing stereocilia of sensory cells. In the inner ear, localized to stereocilia, apical microvilli of sensory cells and kinocilia. In the inner ear, expressed predominantly in sensory hair cells and their stereocilia bundles with higher levels in outer hair cells (OHC) at P1 and in inner hair cells (IHC) at P5. At P1, expression is prominent in each row of stereocilia within bundles including immature shorter stereocilia. Expression is also observed in apical microvilli of sensory cells at P1 and in kinocilia at P1 and P5. In the adult, expression is localized throughout the length of the stereocilia of both OHC and IHC (at protein level). Defects in Grxcr1 are the cause of the pirouette (pi) phenotype which is characterized by vestibular defects and profound deafness with affected mice displaying abnormally thin and slightly shortened sterocilia. Belongs to the GRXCR1 family.