Cholera and Shiga toxin B-subunits: thermodynamic and structural considerations for function and biomedical applications.
The B-subunits of cholera and Shiga toxins are functionally and structurally related proteins with different chain lengths and no sequence similarity. They are responsible for toxin binding to specific glycosphingolipid receptors and intracellular toxin trafficking. Indeed, it is clearly established that B-subunits have the unique capacity of targeting the toxins to a poorly explored intracellular pathway, the retrograde route, allowing the transfer to the cytosol of the associated catalytic A-subunits, by retro-translocation from the endoplasmic reticulum. The B-subunits have also been used as vectors for antigen presentation in immunotherapeutic approaches. It is, however, not known if and how the B-subunits intervene in membrane translocation of the A-subunits and/or antigens to the cytosol. Therefore, it is important to characterise the driving force of pentamer formation, its conformational stability, and toxin-receptor interactions. This review summarises recent studies that have dealt with these topics.
Pina
David G
DG
Laboratoire Trafic et Signalisation, UMR 144 Curie/CNRS, Institut Curie, 26 rue d'Ulm, 75248 Paris Cedex 05, France.
Johannes
Ludger
L
D000595:Amino Acid Sequence; D002772:Cholera Toxin / Q000737:chemistry* / Q000378:metabolism; D008969:Molecular Sequence Data; D011485:Protein Binding; D011487:Protein Conformation; D017510:Protein Folding; D021381:Protein Transport / Q000502:physiology; D011956:Receptors, Cell Surface / Q000378:metabolism*; D022603:Shiga Toxins / Q000737:chemistry* / Q000378:metabolism; D013816:Thermodynamics; D014281:Trihexosylceramides / Q000737:chemistry
D011956:Receptors, Cell Surface; D022603:Shiga Toxins; D014281:Trihexosylceramides; C018549:globotriaosylceramide; D002772:Cholera Toxin