Anavex Life Sciences Corp (AVXL)

[nidan7500]

quote link from Rubyred77...

So Many Dots, so little time...

'The S1R does not have a defined signaling pathway; instead, the dominant accepted model is that the S1R modulates other cellular signaling pathways by acting as a ligand-operated chaperone. (8) In fact, many protein–protein interactions involving S1R and other partners, such as voltage- or ligand-gated ion channels, GPCRs, transporters, or enzymes, have been identified, supporting its chaperone-like activity. (3) Importantly, the ability of S1R to homo- and heteromerize can be regulated by ligands. (9) Therefore, while S1R antagonists favor the formation of higher-order receptor oligomers, agonists promote the opposite, namely, the generation of lower-molecular-weight forms, such as homodimeric or monomeric receptors. In fact, the regulation of S1R oligomerization by ligands constitute the basis for considering this receptor as a ligand-operated chaperone. Specifically, at the interface between the endoplasmic reticulum (ER) and the mitochondrion (mitochondria-associated ER membrane, MAM), S1R interacts with the binding immunoglobulin protein (BiP), a resident chaperone of ER. (3,10-12) Specifically, S1R agonists or a reduction in ER calcium levels prompts the dissociation of S1R and BiP, which disclose the sole intrinsic chaperone activity of S1R and BiP with their respective client proteins. (8) Consistent with this, S1R is a calcium-sensitive chaperone located in the ER, specifically in the MAM, where it exerts an important role in stabilizing this interorganelle region, calcium homeostasis, mitochondrial bioenergetics, and ER stress response. (10,13) In addition, S1R can eventually translocate to the plasma membrane where it interacts with ion channels and GPCR. Finally, S1R can also be found in the nuclear envelope, where it regulates transcription. (10,11)"
The S1R does not have a defined signaling pathway; instead, the dominant accepted model is that the S1R modulates other cellular signaling pathways by acting as a ligand-operated chaperone. (8) In fact, many protein–protein interactions involving S1R and other partners, such as voltage- or ligand-gated ion channels, GPCRs, transporters, or enzymes, have been identified, supporting its chaperone-like activity. (3) Importantly, the ability of S1R to homo- and heteromerize can be regulated by ligands. (9) Therefore, while S1R antagonists favor the formation of higher-order receptor oligomers, agonists promote the opposite, namely, the generation of lower-molecular-weight forms, such as homodimeric or monomeric receptors. In fact, the regulation of S1R oligomerization by ligands constitute the basis for considering this receptor as a ligand-operated chaperone. Specifically, at the interface between the endoplasmic reticulum (ER) and the mitochondrion (mitochondria-associated ER membrane, MAM), S1R interacts with the binding immunoglobulin protein (BiP), a resident chaperone of ER. (3,10-12) Specifically, S1R agonists or a reduction in ER calcium levels prompts the dissociation of S1R and BiP, which disclose the sole intrinsic chaperone activity of S1R and BiP with their respective client proteins. (8) Consistent with this, S1R is a calcium-sensitive chaperone located in the ER, specifically in the MAM, where it exerts an important role in stabilizing this interorganelle region, calcium homeostasis, mitochondrial bioenergetics, and ER stress response. (10,13) In addition, S1R can eventually translocate to the plasma membrane where it interacts with ion channels and GPCR. Finally, S1R can also be found in the nuclear envelope, where it regulates transcription. (10,11)

https://pubs.acs.org/doi/full/10.1021/acschemneuro.3c00206#