Guanine nucleotide exchange factor (GEF) with specificity for RAP2A, it doesn't seems to activate other Ras family proteins (in vitro). Interacts with Ras family proteins (By similarity). Interacts with CCDC124 during cytokinesis. May shuttle between early and late endosomes (By similarity). Localizes to midbody at telophase. Up-regulated in macrophages stimulated with IFNG, GPI-mucins or bacterial lipopolysaccharides (LPS).