7k7a
From Proteopedia
Transmembrane structure of TNFR1
Structural highlights
Disease[TNR1A_HUMAN] Defects in TNFRSF1A are the cause of familial hibernian fever (FHF) [MIM:142680]; also known as tumor necrosis factor receptor-associated periodic syndrome (TRAPS). FHF is a hereditary periodic fever syndrome characterized by recurrent fever, abdominal pain, localized tender skin lesions and myalgia. Reactive amyloidosis is the main complication and occurs in 25% of cases.[1] [2] [3] [4] [5] Genetic variation in TNFRSF1A is associated with susceptibility to multiple sclerosis 5 (MS5) [MIM:614810]. A multifactorial, inflammatory, demyelinating disease of the central nervous system. Sclerotic lesions are characterized by perivascular infiltration of monocytes and lymphocytes and appear as indurated areas in pathologic specimens (sclerosis in plaques). The pathological mechanism is regarded as an autoimmune attack of the myelin sheat, mediated by both cellular and humoral immunity. Clinical manifestations include visual loss, extra-ocular movement disorders, paresthesias, loss of sensation, weakness, dysarthria, spasticity, ataxia and bladder dysfunction. Genetic and environmental factors influence susceptibility to the disease. Note=An intronic mutation affecting alternative splicing and skipping of exon 6 directs increased expression of isoform 4 a transcript encoding a C-terminally truncated protein which is secreted and may function as a TNF antagonist.[6] Function[TNR1A_HUMAN] Receptor for TNFSF2/TNF-alpha and homotrimeric TNFSF1/lymphotoxin-alpha. The adapter molecule FADD recruits caspase-8 to the activated receptor. The resulting death-inducing signaling complex (DISC) performs caspase-8 proteolytic activation which initiates the subsequent cascade of caspases (aspartate-specific cysteine proteases) mediating apoptosis. Contributes to the induction of non-cytocidal TNF effects including anti-viral state and activation of the acid sphingomyelinase. Publication Abstract from PubMedReceptors in the tumor necrosis factor receptor superfamily (TNFRSF) regulate proliferation of immune cells or induce programmed cell death, and many of them are candidates for antibody-based immunotherapy. Previous studies on several death receptors in the TNFRSF including Fas, p75NTR, and DR5 showed that the transmembrane helix (TMH) of these receptors can specifically oligomerize and their oligomeric states have direct consequences on receptor activation, suggesting a much more active role of TMH in receptor signaling than previously appreciated. Here, we report the structure of the TMH of TNFR1, another well studied member of the TNFRSF, in neutral bicelles that mimic a lipid bilayer. We find that TNFR1 TMH forms a defined trimeric complex in bicelles, and no evidences of higher-order clustering of trimers have been detected. Unexpectedly, a conserved proline, which is critical for Fas TMH trimerization, does not appear to play an important role in TNFR1 TMH trimerization, which is instead mediated by a glycine near the middle of the TMH. Further, TNFR1 TMH trimer shows a larger hydrophobic core than that of Fas or DR5, with four layers of hydrophobic interaction along the threefold axis. Comparison of the TNFR1 TMH structure with that of Fas and DR5 reveals reassuring similarities that have functional implications but also significant structural diversity that warrants systematic investigation of TMH oligomerization property for other members of the TNFRSF. The Diversity and Similarity of Transmembrane Trimerization of TNF Receptors.,Zhao L, Fu Q, Pan L, Piai A, Chou JJ Front Cell Dev Biol. 2020 Oct 14;8:569684. doi: 10.3389/fcell.2020.569684., eCollection 2020. PMID:33163490[7] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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