We now know that apicoplast (Trans) membrane proteins can originate from a vesicle and a signal peptide pathway. Normally signal peptide regions are cleaved out of the protein for apicoplast globular proteins and thus I'm assuming apicoplast membrane residing proteins no longer contain these signal peptide regions either? But I read in one paper that proteins targeted to the apicoplast via vesicles can still have these signal peptide regions within them which is confusing.
As the proteins will join the apicoplast membrane via vesicular fusion, will they not have their signal peptide regions cleaved off? so are there still apicoplast membrane proteins which exist in the these membranes with a signal peptide region within their sequence (which also contains a hydrophobic part)?
Article Membrane and luminal proteins reach the apicoplast by differ...
Hi Hiba Riyadh Al-abodi thank you for taking the time to try to answer my question I do appreciate it. But I'm after a different piece of information and I have actually read that paper before; What I want to know more specifically which I cannot find anywhere is:
By what mechanism is the TM-protein transit peptide cleaved off the protein sequence? For the apicoplast inner membrane proteins as we know most~ of those are targeted via the signal pathway. I do know that outer membrane proteins are ~mostly delivered via the vesicle fusion pathway.
Thus are we certain that for these apicoplast inner membrane TM-proteins that the transit peptide sequence is cleaved off? (we know the signal peptide is already cleaved off in the ER lumen etc).
In trying to find the sequence boundary of the transit peptide sequence to the main protein sequence which is what I want to extract. Is there any easier way to find the boundary without resorting to disorder/SS predictions or spending many hours squinting at a tricky Multiple Sequence Alignment? i.e:
When the transit peptide region is cleaved off will the main protein sequence start with Methionine (M)?
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