Enables 1-phosphatidylinositol binding activity and guanyl-nucleotide exchange factor activity. Acts upstream of or within Rho protein signal transduction and positive regulation of transcription by RNA polymerase II. Located in lamellipodium and membrane. Is expressed in nervous system and retina. Orthologous to human MCF2L (MCF.2 cell line derived transforming sequence like). [provided by Alliance of Genome Resources, Apr 2022]