User:Dinoboy10/Transmembrane domain

Lead
A transmembrane domain (TMD) is a membrane-spanning protein domain. They generally adopt an alpha helix topological conformation, although some TMDs such as those in porins can adopt a different conformation like a beta barrel. Because the interior of the lipid bilayer is hydrophobic, the amino acid residues in the transmembrane domain are often hydrophobic, although proteins such as membrane pumps and ion channels can contain polar residues. TMDs vary greatly in length, sequence, and hydrophobicity, adopting organelle-specific properties.

Functions of transmembrane domains
Transmembrane domains are known to perform a variety of functions. These include:


 * Anchoring transmembrane proteins to the membrane. AMPA receptor(cropped).png anchored to the membrane by its transmembrane domain.]]
 * Facilitating molecular transport of molecules such as ions and proteins across biological membranes. Usually hydrophilic residues and binding sites in the TMDs help in this process.
 * Signal transduction across the membrane. Many transmembrane proteins, such as G protein-coupled receptors, receive extracellular signals. TMDs then propagate those signals across the membrane to induce an intracellular effect.
 * Assisting in vesicle fusion. The function of TMDs is not well understood, but they have been shown to be critical for the fusion reaction, possibly as a result of TMDs affecting the tension of the lipid bilayer.
 * Mediating transport and sorting of transmembrane proteins. TMDs have been shown to work in tandem with cytosolic sorting signals, with length and hydrophobicity being the main determinants in TDM sorting. Longer and more hydrophobic TMDs aid in sorting proteins to the cell membrane, whereas shorter and less hydrophobic TMDs are used to retain proteins in the endoplasmic reticulum and the Golgi apparatus. The exact mechanism of this process is still unknown.

Peer Review
That's frustrating. I like the information you have here. You mention that they vary greatly in length, sequence, and hydrophobicity. You could add examples of how these differ. You could also expound upon what role they play in vesicle fusion.EAGMIL (talk) 02:43, 10 December 2021 (UTC)

FYI: Somebody changed the article just a few days ago, so they already added in lots of the changes I had been going to make. So I'm not sure how much new stuff I'll be adding anymore! Dinoboy10 (talk) 05:07, 8 December 2021 (UTC)

This lead is a good start. It looks like you have also gathered some good sources in an another sandbox. I'm interested to see how it all comes together.