The monomeric receptor binding domain of tetrameric α2-macroglobulin binds to cell surface GRP78 triggering equivalent activation of signaling cascades.

@article{Misra2013TheMR,
  title={The monomeric receptor binding domain of tetrameric α2-macroglobulin binds to cell surface GRP78 triggering equivalent activation of signaling cascades.},
  author={Uma Kant Misra and Sturgis Payne and Salvatore Vincent Pizzo},
  journal={Biochemistry},
  year={2013},
  volume={52 23},
  pages={4014-25}
}
α2-Macroglobulin (α2M) is a broad spectrum proteinase inhibitor that when activated by proteinases (α2M*) undergoes a major conformational change exposing receptor recognition sites in each of its four subunits. These complexes bind to two distinct receptors, namely, the low-density lipoprotein receptor-related protein (LRP) and cell surface glucose-regulated protein [Mr ∼ 78000 (GRP78)]. The latter is a very high affinity receptor (Kd = 50-100 pM) whose ligation triggers pro-proliferative and… CONTINUE READING