Abstract
Large spines are stable and important for memory trace formation. The majority of large spines also contains Synaptopodin (SP), an actin-modulating and plasticity-related protein. Since SP stabilizes F-actin, we speculated that the presence of SP within large spines could explain their long lifetime. Indeed, using time-lapse 2-photon-imaging of SP-transgenic granule cells in mouse organotypic tissue cultures we found that spines containing SP survived considerably longer than spines of equal size without SP. Of note, SP-positive spines that underwent pruning first lost SP before disappearing. Whereas the survival time courses of SP-positive (SP+) spines followed conditional two-phase decay functions, SP-negative (SP-) spines and all spines of SP-deficient animals showed single exponential decays. These results implicate SP as a major regulator of long-term spine stability: SP clusters stabilize spines and the presence of SP indicates spines of high stability.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
Funding/Grant sponsor This work was supported by Deutsche Forschungsgemeinschaft (DFG CRC 1080; DE 2741/1-1; DFG DE 551/13-1) and International Max Planck Research School for Neural Circuits (scholarship for K. Y.).
Competing interests / Conflict of Interest Statement The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
