RIAM is strongly expressed in cells of hematopoietic origin. (A-D) Western blot analysis confirms loss of RIAM protein in indicated tissues and cells of RIAM^−/− mice. Levels of talin-1 (A-D), Cal-DAG (B), Kindlin-3 (B-D), and Rap1 (B-D) are unaffected in different organs (A), platelets (B), macrophages (C), and PMNs (D). RIAM levels are reduced in platelets, macrophages, and PMNs isolated from RIAM^+/− mice (B-D). (E) Comparison of RIAM and talin-1 expression in different tissues and hematopoietic cells. GAPDH expression served as loading control. GAPDH, glyceraldehyde 3-phosphate dehydrogenase; sk., skeletal.