Chemotaxis

Gradient direction is sensed by selectively recruiting PH domains to the membrane of the leading edge. PI3K recruited to leading edge, PTEN goes to the back.
GPCR distribution around the cell remains constant
cAMP/ folic acid is detected by GPCRs and Gßg signal causes leading edge to form

LY294002: PI3K inhibitor
GTPgS: non-hydrolysable GTP

CRAC: protein with PH domain that is needed to activate adenylyl cyclase, takes signal from GPCR (Gb)