Figure 4.

Fragments (16 kDa) inhibit bFGF-dependent MAPK tyrosine phosphorylation and activity whereas full length hormones stimulate these processes in the absence of bFGF. BBCE cells were treated for 5 min with the purified 16-kDa fragments (10 nM) and bFGF (250 pM) or for 10 min with the intact hormones (10 nM) but without bFGF or were left untreated for control. (A) P-Tyr, Western blots with the antityrosine antibody at the level of the MAPK p42 and p44; MAPK, the Western blot shown in the P-Tyr panel, stripped and reprobed with an anti-MAPK antibody. (B) In-gel MAPK activity. Numbers at the bottom of the histograms represent the number of experiments performed.