Before revision:  We calculate the fundamental limits of the signaling specificity and accuracy of a pleiotropic receptor arising from the molecular noise both at the receptor level and downstream. We further investigate the effects of common signaling schemes such as Kinetic Proofreading (KPR) and show that KPR does not necessarily increase the signaling specificity once the effects of molecular noise are taken into account .
After revision:  We calculate the fundamental limits of the signaling specificity and accuracy of such signaling schemes .