Fig. 7. SHP-2 is phosphorylated and interacts with FRS in vivo. (A) Transverse cryosections through the heart of control Xenopus embryos stained with tropomyosin to mark cardiac tissue (Tmy; green), DAPI to mark cell nuclei (blue), and anti-total SHP-2, anti-phospho-542 SHP-2 or anti-phospho-580 SHP-2 (all shown in red). Arrows denote endocardial cells that are negative for SHP-2. All samples from stage 37. (B) SHP-2 interacts with FRS in vivo. Hearts from FL-HA-SHP-2-derived embryos were dissected at stage 35 and immunoprecipitated with an anti-SHP-2 antibody (+) or beads with no antibody (-). Western analysis was then performed using antibodies specific for total SHP-2, phospho-542 SHP-2 and FRS-2. Note that the level of SHP-2 phopho-542 in the input was below levels of detection.