Fig. 1.
External environmental cues can stimulate neuronal calcium (Ca2+) influx via effects on extracellular matrix components (notably CCN proteins and hemicentin (HMCN1)), a variety of transmembrane receptors, and intracellular signalling cascades; the expression/activity of many of these proteins is differentially sensitive to sulfated and free steroids, and/or is affected by steroid sulfatase (STS) deficiency (indicated with an asterisk symbol)