Generation of RIAM^−/− mice. (A) Schematic representation of RIAM targeting. The RIAM locus of murine ES cells was targeted by homologous recombination to generate an allele with loxP sites flanking exons 3 and 4. The resulting RIAM conditional mice were crossed with a Cre-deleter strain to remove exons 3 and 4, along with the Neo cassette, and thereby generate RIAM^+/− mice that were crossed to produce RIAM^−/− mice. (B) Immunmoblot for RIAM and RhoGDI of lysates of T and B cells isolated from spleens of RIAM^+/+ and RIAM^−/− mice. (C) Immunoblot for lamellipodin and RhoGDI of lysates of of MDA-MB-231 human breast cancer cells, as well as the extracts of brain, spleen, and platelets from mice with the indicated genotype.