IL6 and infection: Our study demonstrates that RasGRP3, a regulator of both Ras and Rap1, negatively regulates the production of proinflammatory cytokines (especially IL-6) by activating Rap1 and inhibiting ERK1/2 activation in response to low levels of TLR agonists, which may serve as an early regulatory machinery to limit inflammatory response of macrophages to feeble infection.