myosin VIIA

Normal function

The MYO7A gene provides instructions for making a protein called myosin VIIA, which is part of a group of proteins called unconventional myosins. These proteins, which have similar structures, help transport molecules within cells. Myosins interact with actin, a protein that is important for cell movement and shape. Researchers believe that myosins use long filaments of actin as tracks along which to transport other molecules.

Myosin VIIA is made in the inner ear and in the retina, which is the light-sensitive tissue at the back of the eye. In the inner ear, myosin VIIA plays a role in the development and maintenance of hairlike projections called stereocilia. Stereocilia, which are rich in actin, line the inner ear and bend in response to sound waves. This bending motion is critical for converting sound waves to nerve impulses, which are then transmitted to the brain. Stereocilia are also elements of the vestibular system, the part of the inner ear that helps maintain the body's balance and orientation in space. Bending of these stereocilia is needed to transmit signals from the vestibular system to the brain.

In the retina, myosin VIIA is found primarily in a thin layer of cells called the retinal pigment epithelium (RPE). Myosin VIIA probably plays a role in the development and maintenance of this tissue, which supports and nourishes the retina. Research suggests that one function of myosin VIIA is to carry small sacs of pigment (called melanosomes) within the RPE. This pigment is necessary for normal vision. Myosin VIIA is also found in other parts of the retina, where it likely carries additional proteins and molecules that are important for vision.

Conditions referring to this gene or chromosome

• Usher syndrome

• Nonsyndromic hearing loss

• Age-related hearing loss

Other names

DFNA11

DFNB2

MYO7A_HUMAN

myosin VIIA (Usher syndrome 1B (autosomal recessive, severe))

NSRD2

USH1B