H. V. Wilson worked with sponges to gain some insight into exactly what was responsible for holding adjacent cells together. He exposed two species of differently pigmented sponges to a chemical that disrupted the cell-cell interaction (cell junctions), and the cells of the sponges dissociated. Wilson then mixed the cells of the two species and removed the chemical that caused the cells to dissociate. Wilson found that the sponges reassembled into two separate species. The cells from one species did not interact or form associations with the cells of the other species. How do you explain the results of Wilson's experiments?
The rER is bears many ribosomes on its outer surface giving it a rough appearance as seen under the microscope; hence, the name. The presence of ribosomes on rER is an indication that the latter is involved in protein synthesis and secretion . The organelle synthesizes and secretes serum proteins (such as albumin ) in the liver , and hormones (such as insulin ) and other substances (such as milk ) in the glands . Nevertheless, the ribosomes that give the endoplasmic reticulum a 'rough' appearance are not always bound to the ER. They bind to it when it starts to synthesize membrane-bound proteins destined for sorting. A cue is a particular protein-nucleic acid complex that forms in the cytosol .
The unfolded protein response (UPR) is a cellular stress response related to the endoplasmic reticulum.  The UPR is activated in response to an accumulation of unfolded or misfolded proteins in the lumen of the endoplasmic reticulum. The UPR functions to restore normal function of the cell by halting protein translation , degrading misfolded proteins, and activating the signaling pathways that lead to increasing the production of molecular chaperones involved in protein folding . Sustained overactivation of the UPR has been implicated in prion diseases as well as several other neurodegenerative diseases and the inhibition of the UPR could become a treatment for those diseases.