Review Article

Actin-Dependent Alterations of Dendritic Spine Morphology in Shankopathies

Figure 3

Activity dependent spine morphology alteration. Upon synaptic activation or in case of LTP, rapid actin remodeling favors the formation of filamentous or F actin. This can have twofold effects: one is the spine enlargement and the other one is that actin is able to anchor additional receptors at the PSD. On the other hand, synaptic depression or LTD is often coupled with spine shrinkage. This is realized by the depolymerization of F actin. In addition to such depolymerization, the number of receptors may be decreased, thus making the dendritic spine less responsive to synaptic stimulation. The changes in actin remodeling and receptor trafficking can occur together or independent of each other. Spine shrinkage and enlargement also depend on scaffolding proteins of the Shank family that increase in number at the PSD upon LTP and decrease upon LTD.