Fig. 5. Pharmacological blockade of receptor tyrosine kinases (RTK) by K252a or by the selective Met inhibitor PHA665752 does not affect Sema4d-induced inhibition of ureteric branching in metanephroi cultured at E12. (A-D) Typical examples of anti-calbindin-stained mouse metanephroi cultured with either Sema4d or mock medium in the presence or absence of the RTK inhibitor, K252a (200 nM). (E-H) Blockade of RTKs by K252a significantly reduced ureteric branching (E,F) and size (G,H) in mock-treated kidneys, but did not affect Sema4d-induced modulation of these parameters in developing kidneys. (I-L) Similar results were obtained when using the selective Met inhibitor PHA665752. ^*P<0.001 when compared with mock or Sema4d alone; Student's paired t-test.