Membrane steroid receptors (mSRs), also called extranuclear steroid receptors, are a class of cell surface receptors activated by endogenous steroids that mediate rapid, non-genomic signaling via modulation of intracellular signaling cascades. [1] [2] [3] [4] mSRs are another means besides classical nuclear steroid hormone receptors (SHRs) for steroids to mediate their biological effects. [1] [2] [3] [4] SHRs can produce slow genomic responses or rapid, non-genomic responses in the case of mSRs. [5]
Known groups of mSRs, by ligand, include: [a]
In addition, PDIA3 is a membrane receptor for the secosteroid calcitriol, the activated form of Vitamin D. [8]