The SPRY domain-containing protein 4 (SPRYD4) is a member of a family of proteins whose sole common characteristic is the presence of a SPRY domain. SPRY domains are structural domains that were first described in the fungal Dictyostelium discoideum tyrosine kinase spore lysis A. In most systems SPRY domains provide binding sites for regulatory proteins or intramolecular binding sites that maintain the structural integrity of a protein. SPRYD4 is ubiquitously expressed and is most abundant in kidney, brain, bladder, thymus and stomach. Little is known of the function of the SPRYD4 protein.