Secretion Regulating Guanine Nucleotide Exchange Factor (SERGEF)

Human DELGEF encodes a deduced 458-amino acid, 50-kD protein containing a repeat structure characterized by highly conserved glycines that form a 3-dimensional structure resembling a 7-blade propeller. The human and mouse proteins share 80% sequence identity. DELGEF2 encodes a deduced 288-amino acid peptide that has a deletion of 2 of the 7 repeat units. Immunofluorescence studies showed that DELGEF1 localizes to the cytoplasm and nucleus, whereas DELGEF2 colocalizes with mitochondria. Northern blot analysis detected ubiquitous expression of a 1.4-kb DELGEF transcript, with highest expression in brain, skeletal muscle, prostate, and ovary, and lowest expression in placenta, lung, and liver. An additional 1.0-kb transcript was detected in testis.