Tumour necrosis factor receptors

Both receptor types are members of the NGF receptor superfamily and exhibit the characteristic four (cysteine-rich) repeat units in their extracellular domain. The extracellular domains of TNF-R55 and TNF-R75 exhibit only 28 per cent homology and their intracellular domains are devoid of any homology, indicating the likely existence of distinct signalling mechanisms. 

It appears that TNF-R55 is capable of mediating most TNF activities, whereas the biological activities induced via the TNF-R75 receptor are more limited. For example, TNF s cytotoxic activity, as well as its ability to induce synthesis of various cytokines and prostaglandins, is all mediated mainly/exclusively by TNF-R55. TNF-R75 appears to play a more prominent role in the induction of synthesis of T-lymphocytes. All of the biological activities mediated by TNF-R75 can also be triggered via TNF-R55, and usually at much lower densities of receptors. TNF-R75 thus appears to play more of an accessory role, mainly to enhance effects mediated via TNF-R55. 

The exact molecular mechanisms by which TNF-induced signal transduction are mediated remain to be characterized in detail. Oligomerization of the receptors is often followed by their phosphorylation, most likely by accessory kinases that associate with the intracellular domain of the receptor (neither receptor type displays intrinsic protein kinase activity). The existence of several phosphoproteins capable of associating with (the intracellular domain of) TNF-R55 and TNF-R75 have also been established. Following clustering of the TNF receptors, these 

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The genosensor device described in this section can detect a 110 bp region of the TNFRSF21 gene (tumour necrosis factor receptor superfamily, member 21 precursor), bases comprise between 1859 and 1968, both included. This gene is previously inserted in the plasmid expression vector pFLAGCMVl, and amplified by PCR. Then, the PCR product is detected on the genosensor. 

Both involve receptors of the tumour necrosis factor receptor (TNFR) family coupled to extrinsic signals. 

TRADD tumour necrosis factor receptor-associated death domain... 

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