Synaptopodin is required for long-term depression at Schaffer collateral-CA1 synapses

Synaptopodin (SP), an actin-associated protein found in telencephalic neurons, affects synaptic and structural plasticity. While being required for longterm depression (LTD) mediated by metabotropic glutamate receptor (mGluR-LTD), little is known about its role in other forms of LTD induced by low frequency stimulation (LFS-LTD) or spike-timing dependent plasticity (STDP). Using SP-deficient mice (SPKO), we have here demonstrated that the presence of SP is mandatory for normal LTD expression. On the contrary, long-term potentiation (LTP), albeit diminished in SPKO, is still present and can be easily recovered by increasing the stimulation frequency. Our study shows, for the first time, the role of SP in a more physiological form of induction of synaptic plasticity.