Search results
Results from the WOW.Com Content Network
The release of calsequestrin-bound calcium (through a calcium release channel) triggers muscle contraction. The active protein is not highly structured, more than 50% of it adopting a random coil conformation. [2] When calcium binds there is a structural change whereby the alpha-helical content of the protein increases from 3 to 11%. [2]
Several neurodegenerative and other diseases are believed to result from the accumulation of amyloid fibrils formed by misfolded proteins, the infectious varieties of which are known as prions. [4] Many allergies are caused by the incorrect folding of some proteins because the immune system does not produce the antibodies for certain protein ...
Where misfolding proteins continually breach quality control, chaperones including Grp78 facilitate its removal from the ER through retrotranslocation, where it is broken down by the ubiquitin-proteasome pathway as part of the ERAD system. Successful protein folding requires a tightly controlled environment of substrates that include glucose to ...
Porosomes are few nanometers in size and contain many different types of protein, especially chloride and calcium channels, actin, and SNARE proteins that mediate the docking and fusion of the vesicles with the cell membrane. Once the vesicles have docked with the SNARE proteins, they swell, which increases their internal pressure.
UGGT, or UDP-glucose:glycoprotein glucosyltransferase, is a soluble enzyme resident in the lumen of the endoplasmic reticulum (ER). [1]The main function of UGGT is to recognize misfolded glycoproteins and transfer a glucose (Glc) monomer (monoglucosylate) to the terminal mannose of the A-branch of the glycan on the glycoprotein.
Because the ubiquitin–proteasome system (UPS) is located in the cytosol, terminally misfolded proteins have to be transported from the endoplasmic reticulum back into cytoplasm. Most evidence suggest that the Hrd1 E3 ubiquitin-protein ligase can function as a retrotranslocon or dislocon to transport substrates into the cytosol.
Calcium buffering describes the processes which help stabilise the concentration of free calcium ions within cells, in a similar manner to how pH buffers maintain a stable concentration of hydrogen ions. [1] The majority of calcium ions within the cell are bound to intracellular proteins, leaving a minority freely dissociated. [2]
Misfolded proteins can form protein aggregates or amyloid fibrils, get degraded, or refold back to its native structure. In molecular biology , protein aggregation is a phenomenon in which intrinsically-disordered or mis-folded proteins aggregate (i.e., accumulate and clump together) either intra- or extracellularly.