Regulates the dendritic spine distribution of CTTN/cortactin in hippocampal neurons, thus controls dendritic spinogenesis and dendritic spine maintenance. Interacts with CTTN/cortactin SH3 domain. Interacts with STRN, STRN4/zinedin and MOB4/phocein; this interaction may regulate dendritic spine distribution of STRN and STRN4 in hippocampal neurons. Activation of glutamate receptors weakens the interaction with STRN and STRN4. Remains associated with dendritic spines even after glutamate stimulation. Highest expression in brain. Also expressed in kidney, pancreas, lung, heart, liver, skeletal muscle and placenta.