Communication, renegotiation, and the scope for collusion

Abstract: We experimentally study the effect of communication in a game where cooperation is consistent with equilibrium play if players share an understanding that cheating will be punished. Consistent with communication acting as a coordinating device, pre-play messages including a credible threat to punish cheating are the most effective type of message for improving collusion. Sending promises to collude also improves cooperation. Credible threats do not emerge in a limited message space treatment that allows for threats of punishment, suggesting that communication is inherently different with only a limited message space. Contrary to theory, allowing for renegotiation increases collusion

Inhibitory Effects of Robo2 on Nephrin: A Crosstalk between Positive and Negative Signals Regulating Podocyte Structure

Robo2 is the cell surface receptor for the repulsive guidance cue Slit and is involved in axon guidance and neuronal migration. Nephrin is a podocyte slit-diaphragm protein that functions in the kidney glomerular filtration barrier. Here, we report that Robo2 is expressed at the basal surface of mouse podocytes and colocalizes with nephrin. Biochemical studies indicate that Robo2 forms a complex with nephrin in the kidney through adaptor protein Nck. In contrast to the role of nephrin that promotes actin polymerization, Slit2-Robo2 signaling inhibits nephrin-induced actin polymerization. In addition, the amount of F-actin associated with nephrin is increased in Robo2 knockout mice that develop an altered podocyte foot process structure. Genetic interaction study further reveals that loss of Robo2 alleviates the abnormal podocyte structural phenotype in nephrin null mice. These results suggest that Robo2 signaling acts as a negative regulator on nephrin to influence podocyte foot process architecture