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Fig. 12. Model for Rho-dependent HIF-1
and angiogenesis activation during
hypoxia. This schema summarizes the main steps that we have identified to play
crucial roles in the induction of HIF-1
mediated by Rho GTPases. The
involvement of ROS production was abolished by DPI and prevented Cdc42 and
RhoA induction. Also, the C3 toxin that abolished RhoA expression prevented
HIF-1
induction under hypoxic conditions. The kinetics demonstrated
that Cdc42, Rac1 and RhoA are upregulated sequentially by hypoxia but it
remains to be established whether there is a hierarchy of activation in Rho
GTPase cascades (dotted arrows).