Hysteresis in CaMKII activity: A stochastic model

摘要

Calcium/calmodulin dependent protein kinase II (CaMKII) plays a crucial role in the induction of Long Term Potentiation. Several mathematical models have been developed to predict the activity levels of CaMKII in the physiological condition and its molecular switch properties. This paper attempts to study the hysteresis property of CaMKII using a stochastic model. It was observed that hysteresis exists under physiological conditions, but the width of the hysteresis band depends on the concentration of protein phosphatase 1 (PP1). The hysteresis band was maximum at low concentrations of PP1 and reduced with increasing concentrations of PP1. It was also observed that the number of phosphorylated subunits saturates beyond a threshold value of calcium signal.