A biochemical analysis of the constraints of tail-anchored protein biogenesis
| Autor: | Pawel Leznicki, Stephen High, Jim Warwicker |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2011 |
| Předmět: |
Cytb5
cytochrome b5 TRC40 transmembrane domain recognition complex of 40 kDa tail-anchored protein (TA protein) Endoplasmic Reticulum Biochemistry Hsp heat-shock protein Polyethylene Glycols 0302 clinical medicine Cytosol mPEG methoxypoly(ethylene glycol) PEG poly(ethylene glycol) Drosophila Proteins Lipid bilayer OPG opsin glycosylation tag EndoH endoglycosidase H 0303 health sciences PEGylation BODIPY® boron dipyrromethene (4 4-difluoro-4-bora-3a 4a-diaza-s-indacene) Recombinant Proteins Transmembrane domain Tetratricopeptide Protein Transport Membrane BMH bis(maleimido)hexane Research Article Protein Binding TA tail-anchored Biology SRP signal recognition particle TMS transmembrane segment SGTA small glutamine-rich tetratricopeptide repeat-containing protein α ER endoplasmic reticulum 03 medical and health sciences IASD 4-acetamido-4′-[(iodoacetyl)amino]stilbene-2 2′-disulfonate Animals Humans PDI protein disulfide-isomerase Molecular Biology 030304 developmental biology Endoplasmic reticulum HisTrx histidine–thioredoxin transmembrane domain recognition complex of 40 kDa (TRC40) Membrane Proteins Cell Biology Cytochromes b5 small glutamine-rich tetratricopeptide repeat-containing protein α (SGTA) Biophysics Sec61β cytochrome b5 (Cytb5) Get guided entry of tail-anchored proteins Carrier Proteins 030217 neurology & neurosurgery Biogenesis SEC Translocation Channels Molecular Chaperones |
| Zdroj: | Biochemical Journal |
| ISSN: | 1470-8728 0264-6021 |
| Popis: | TA (tail-anchored) proteins utilize distinct biosynthetic pathways, including TRC40 (transmembrane domain recognition complex of 40 kDa)-mediated, chaperone-dependent and/or unassisted routes to the ER (endoplasmic reticulum) membrane. We have addressed the flexibility of cytosolic components participating in these pathways, and explored the thermodynamic constraints of their membrane insertion, by exploiting recombinant forms of Sec61β and Cytb5 (cytochrome b5) bearing covalent modifications within their TA region. In both cases, efficient membrane insertion relied on cytosolic factors capable of accommodating a surprising range of covalent modifications to the TA region. For Sec61β, we found that both SGTA (small glutamine-rich tetratricopeptide repeat-containing protein α) and TRC40 can bind this substrate with a singly PEGylated TA region. However, by introducing two PEG [poly(ethylene glycol)] moieties, TRC40 binding can be prevented, resulting in a block of subsequent membrane integration. Although TRC40 can bind Sec61β polypeptides singly PEGylated at different locations, membrane insertion is more sensitive to the precise location of PEG attachment. Modelling and experimentation indicate that this post-TRC40 effect results from an increased energetic cost of inserting different PEGylated TA regions into the lipid bilayer. We therefore propose that the membrane integration of TA proteins delivered via TRC40 is strongly dependent upon underlying thermodynamics, and speculate that their insertion is via a phospholipid-mediated process. |
| Databáze: | OpenAIRE |
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