Sandbox Reserved 818: Difference between revisions
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==Binding of pertussis toxin to its cellular targets== | ==Binding of pertussis toxin to its cellular targets== | ||
After being secreted, pertussis toxin (PTX) can interact with almost all mammalian cells, which explains the variety of biological activities of the toxin. <br /> | After being secreted, pertussis toxin (PTX) can interact with almost all mammalian cells, which explains the variety of biological activities of the toxin. <br /> | ||
No specific receptors for PTX have been identified but many cell surface '''sialoglycoproteins''' are involved in the binding of PTX | No specific receptors for PTX have been identified but many cell surface '''sialoglycoproteins''' are involved in the binding of PTX | ||
<ref name="Peppler (1988)"> | |||
Armstrong,G. D.,Howard,L. A. & M S Peppler (1988) Use of glycosyltransferases to restore pertussis toxin receptor activity to asialoagalactofetuin. J. Biol. Chem., 263: 8677-8684. | |||
</ref> | |||
, together with '''glycoproteins''': sugar moieties allow the recognition of the toxin and the carbohydrate sequence '''NeuAcα(2,6)-Galβ4GlcNAc''' is particularly important but sugar sequence alone is not sufficient | |||
<ref name="Peppler (1988)"> | |||
Brennan, M. J., David, J. L., Kenimer, J. G., & Manclark, C. R. (1988). Lectin-like binding of pertussis toxin to a 165-kilodalton Chinese hamster ovary cell glycoprotein. Journal of Biological Chemistry, 263(10), 4895-4899. | |||
</ref> | |||
<br /> | |||
PTX binds its target cells through the ''B oligomer'' : ''S2'' and ''S3'' subunits contains at least two '''carbohydrate-binding sites''' | PTX binds its target cells through the ''B oligomer'' : ''S2'' and ''S3'' subunits contains at least two '''carbohydrate-binding sites''' | ||
<ref name="Read (1994)"> | |||
Stein, P. E., Boodhoo, A., Armstrong, G. D., Heerze, L. D., Cockle, S. A., Klein, M. H., & Read, R. J. (1994). Structure of a pertussis toxin–sugar complex as a model for receptor binding. Nature Structural & Molecular Biology, 1(9), 591-596. | |||
</ref> | |||
. The N-terminal regions of these subunits are involved in receptor binding and the C-terminal domains of S2 and S3 adopt a fold found in other carbohydrate-binding proteins [73]. <br /> | |||
The B oligomer of PTX is involved in some biological activities of the toxin, independently of the enzyme activity. Thus '''Asn105''' in ''S2'' and '''Lys103''' in ''S3'' are important for the mitogenic activity of pertussis toxin on murine T lymphocytes | The B oligomer of PTX is involved in some biological activities of the toxin, independently of the enzyme activity. Thus '''Asn105''' in ''S2'' and '''Lys103''' in ''S3'' are important for the mitogenic activity of pertussis toxin on murine T lymphocytes | ||
<ref name="Locht93"> | |||
Lobet, Y., Feron, C., Dequesne, G., Simoen, E., Hauser, P., & Locht, C. (1993). Site-specific alterations in the B oligomer that affect receptor-binding activities and mitogenicity of pertussis toxin. The Journal of experimental medicine, 177(1), 79-87. | |||
</ref> | |||
, but not on human T cells | |||
<ref name="Klein93"> | |||
Loosmore, S., Zealey, G., Cockle, S., Boux, H., Chong, P. E. L. E., Yacoob, R., & Klein, M. (1993). Characterization of pertussis toxin analogs containing mutations in B-oligomer subunits. Infection and immunity, 61(6), 2316-2324. | |||
</ref>. | |||
==Toxin entry and trafficking in target cells== | ==Toxin entry and trafficking in target cells== | ||
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<references/> | <references/> | ||
