Function: Probable guanine nucleotide exchange factor. similarity: Contains 1 N-terminal Ras-GEF domain. similarity: Contains 1 Ras-associating domain. similarity: Contains 1 Ras-GEF domain. subunit: Interacts with Ras. tissue specificity: Expressed in a wide variety of tissues with strong expression being seen in the heart, brain, kidney, spleen and testis.