Synaptotagmin-4, also known as SYT4, belongs to the synaptotagmin family proteins. Synaptotagmins are a large gene family of synaptic vesicle type III integral membrane proteins that function as regulators of both exocytosis and endocytosis and are involved in neurotransmitter secretion from small secretory vesicles. SYT4 is expressed in neuronal tissues, and has the highest mRNA levels in the hippocampus. The proximity of the SYT4 gene to markers of several psychiatric disorders suggest an involvement of SYT4 in human diseasee. Recombinant human SYT4 protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.