Dock4-Ex49 is a splice variant of the signalling protein Dock4 (<u>D</u>edicator <u>o</u>f <u>c</u>yto<u>k</u>inesis 4). It has been found in the brain, inner ear and eye. It is able to bind and activate the small G protein Rac and may regulate the organisation of the actin cytoskeleton in the Stereocilia of the inner ear.