signaling molecule
5.Also, the researchers discoered that the initiating mechanism is a lack of the key signaling molecule nitric oxide in the artery wall, which has multiple beneficial roles in the cardioascular system, as well as made a connection between nitric oxide and the proteins responsible for angiotensin II actiity.
7.Interaction between Chaperone and Interleukin-2 Proliferation Signaling--Functional Study of Signal Molecule Chaperone Hsp90

