(a and b) Western blot analysis shows that HGF induced Akt (a) and Erk-1/2 (b) phosphorylation and activation in human podocytes. Cell lysates were immunoblotted with specific antibodies against phosphospecific Akt and total Akt (a), or phospho-specific Erk1/2 and glyceraldehyde 3 phosphate dehydrogenase (GAPDH) (b). PI3K inhibitor (wortmannin, 10 nM) or Mek1 inhibitor (PD98059, 10 μM) effectively blocked the HGF-induced Akt and Erk-1/2 activation, respectively. (c and d) Blockade of Akt activation by wortmannin, but not Erk-1/2 activation by PD98059, abolished the antiapoptotic effect of HGF in both mouse (c) and human podocytes (d). Cell lysates were immunoblotted with specific antibodies against pro-caspase-3 or cleaved caspase-3, respectively.