FGF-R4, fibroblast growth factor receptor 4, also known as CD334, protein tyrosine kinase. It is a member of the fibroblast growth factor receptor family. These receptor proteins play an important role in cell division, regulation of cell growth and maturation, angiogenesis, wound healing and embryonic development. FGF-R4 protein interacts with specific growth factors to transmit signals from the extracellular environment to the nucleus, which enables cells to divide, move or mature by turning on or off genes that help cells adapt to environmental changes. Although the exact function of FGF-R4 is still unclear, studies have shown that the gene is involved in muscle development and the maturation of osteocytes in the skull. The FGF-R4 gene may also play a role in the development and maintenance of specialized cells (called central cones) in the photosensitive layer (retina) at the back of the eye.