Figure 2: Models for the GM130–Cdc42 crosstalk.
From: Spatial control of Cdc42 signalling by a GM130–RasGRF complex regulates polarity and tumorigenesis
Schematic representation of two different models. On the left-hand side: GM130 acts as a scaffold for a Cdc42–GEF at the Golgi. In this case, a GEF should be located at the Golgi in a GM130-dependent manner. Upon GM130 depletion, the GEF is lost from the Golgi and subsequently, Cdc42-GTP doesn’t accumulate at the organelle. In the second scenario (right-hand side), GM130 binds to an inhibitor of Cdc42, protecting the small GTPase from inactivation. If GM130 is lost, the inhibitor will bind to Cdc42 in places other than the Golgi, thereby preventing a GEF-mediated activation of Cdc42. In this way, Cdc42-GTP will not be accumulated at the Golgi.
