Figure 2.

Signaling pathways of RAS GTPase. Receptor tyrosine kinases (RTKs)-mediated activation of RAS in the presence (“+”) and absence (“-“) of ligand is shown as an example. However, multiple upstream regulators of RAS exist. The SHC-GRB2-SOS complex promotes the exchange of GDP to GTP and thereby switching RAS GTPase to the active conformation. Hence, signaling is propagated through the diverse pathways of RAS such as the most prominent RAF/MEK/ERK cascade. RAS-mediated PI3-kinase (PI3K) activation results in protein kinase B (AKT) activation, which is inhibited by phosphatase PTEN (illustrated by T-bar). TIAM1/RAC and RAL-GEF/RAL are involved in cytoskeletal dynamics and cell migration. PLCε/DAG/PKC is associated with Ca²⁺-dependent cellular functions. AF6 forms electrical synapses by localizing at gap junctions. RIN controls axonal pathfinding and via RAB endomembrane signaling. RASSF promotes apoptosis and Canoe regulates cellular polarity.