Table 2.

Summary of major miRNAs implicated in synaptic development and function

MicroRNA	Effect	Known Targets	Source
miR-132	Increased dendritic spine growth (canonical); decreased spine density?	p250RhoGTPase	Kosik, 2009; Schratt, 2009; Siegel et al., 2011
miR-134	Electrical balance of EPSC/IPSC Decreased growth and maturation of dendritic spines	? LIMK1	Schofield et al., 2010; Kosik,2009; Schratt, 2009; Siegel et al., 2011
miR-138	Decreased dendritic spine growth, no change in abundance of synapses	LYPLA1, APT1	Kosik, 2009; Schratt, 2009; Siegel et al., 2011
miR-491	Electrical balance of EPSC/IPSC	?	Schofield et al., 2010

Three miRNAs that control the morphology and subsequently the function of synapses are miR-132, -134, and -138. Growth effects are chiefly mediated through signaling cascades: miR-134 acts on the Rac-LIMK1 cascade while miR-132 and -138 target the RhoA-ROCK cascade.