Rtks can activate the enzyme phosphoinositide 3-kinase, which phosphorylates inositol phopholipids; these phospholipids then serves as docking sites that recruit specific intracellular signaling proteins to the plamsa membrane. RTKs may activate various pathways including; the MAP-kinae signalling module, the Ras signalling pathway, and the phospholipase C/inostol phospholipid signaling pathway.
you are using your shoulder muscle. The reason you are using this muscle is when you put your arm strait up there is no reason to use a bicep or tricep muscle.
