Swiprosin-1/Efhd2 (Efhd2) is highly expressed in the CNS during development
and in the adult. EFHD2 is regulated by Ca2+ binding, stabilizes F-actin, and
promotes neurite extension. Previous studies indicated a dysregulation of
EFHD2 in human Alzheimer's disease brains. We hypothesized a detrimental
effect of genetic ablation of Efhd2 on hippocampal integrity and specifically
investigated adult hippocampal neurogenesis. Efhd2 was expressed throughout
adult neuronal development and in mature neurons. We observed a severe
reduction of the survival of adult newborn neurons in Efhd2 knockouts,
starting at the early neuroblast stage. Spine formation and dendrite growth of
newborn neurons were compromised in full Efhd2 knockouts, but not upon cell-
autonomous Efhd2 deletion. Together with our finding of severe hippocampal
tauopathy in Efhd2 knockout mice, these data connect Efhd2 to impaired
synaptic plasticity as present in Alzheimer's disease and identify a role of
Efhd2 in neuronal survival and synaptic integration in the adult hippocampus