Abstract
The postsynaptic density (PSD) is a membrane associated protein-rich organelle found in the dendritic processes of mammalian neurons. The structure has been demonstrated to be rich in calcium/calmodulin-dependent protein kinase II (CaMKII), and within the confines of the structure the kinase is preferentially dephosphorylated by protein phosphatase 1. Analysis of endogenous PPI and CaMKII protein levels and PPI activity levels suggests CaMKli autophosphorylation rate saturates PPI dephosphorylation rate after periods of high Ca *in the PSD. The unique biochemical properties of CaMKli have long been established as interesting to long-term potentiation (L TP) and memory correlates in the synapse. It is proposed that a balance of autonomous CaMKII autophosphorylation and protein phosphatase 1 (PP 1) dependent dephosphorylation in the postsynaptic density could together act as a bistable memory switch in the PSD. Here I establish a method to address this proposal using in vitro methods with an in vivo preparation, and establish a timecourse for PSD-bound PPI dephosphorylation of CaMKII.