IQSEC3 (IQ motif and SEC7 domain-containing protein 3), also known as KIAA1110, is a 1,182 amino acid protein that belongs to the BRAG family. Localizing to the cytoplasm, IQSEC3 is expressed predominantly in adult brain, where it is observed predominantly in the cerebral cortex and olfactory bulb, with no expression found in the fetal brain. IQSEC3 contains an IQ domain, a PH domain and a SEC7 domain, and interacts with SAP 97 and PSD-95. Acting as a guanine nucleotide exchange factor (GEF) for ARF1, IQSEC3 is encoded by a gene that maps to human chromosome 12p13.33 and mouse chromosome 6 F1. Mutations to the gene encoding IQSEC2 have been linked to non-syndromic X-linked intellectual disability, while both IQSEC1 and IQSEC3 may be candidates for autosomal ID screening. IQSEC3 exists as two alternatively spliced isoforms.