@article {2017|2036, title = {VLITL is a major cross-β-sheet signal for fibrinogen Aα-chain frameshift variants.}, journal = {Blood}, volume = {130}, year = {2017}, month = {2017 12 21}, pages = {2799-2807}, abstract = {

The first case of hereditary fibrinogen Aα-chain amyloidosis was recognized \>20 years ago, but disease mechanisms still remain unknown. Here we report detailed clinical and proteomics studies of a French kindred with a novel amyloidogenic fibrinogen Aα-chain frameshift variant, Phe521Leufs, causing a severe familial form of renal amyloidosis. Next, we focused our investigations to elucidate the molecular basis that render this Aα-chain variant amyloidogenic. We show that a 49-mer peptide derived from the C-terminal part of the Phe521Leufs chain is deposited as fibrils in the patient\&$\#$39;s kidneys, establishing that only a small portion of Phe521Leufs directly contributes to amyloid formation in vivo. In silico analysis indicated that this 49-mer Aα-chain peptide contained a motif (VLITL), with a high intrinsic propensity for β-aggregation at residues 44 to 48 of human renal fibrils. To experimentally verify the amyloid propensity of VLITL, we generated synthetic Phe521Leufs-derived peptides and compared their capacity for fibril formation in vitro with that of their VLITL-deleted counterparts. We show that VLITL forms typical amyloid fibrils in vitro and is a major signal for cross-β-sheet self-association of the 49-mer Phe521Leufs peptide identified in vivo, whereas its absence abrogates fibril formation. This study provides compelling evidence that VLITL confers amyloidogenic properties to Aα-chain frameshift variants, yielding a previously unknown molecular basis for the pathogenesis of Aα-chain amyloidosis.

}, keywords = {Amino Acid Motifs, Amino Acid Sequence, Amyloid, Amyloidosis, Familial, Fibrinogen, Frameshift Mutation, Humans, Kidney, Protein Conformation, beta-Strand}, issn = {1528-0020}, doi = {10.1182/blood-2017-07-796185}, author = {Garnier, Cyrille and Briki, Fatma and Nedelec, Brigitte and Le Pogamp, Patrick and Dogan, Ahmet and Rioux-Leclercq, Nathalie and Goude, Renan and Beugnet, Caroline and Martin, Laurent and Delpech, Marc and Bridoux, Frank and Grateau, Gilles and Doucet, Jean and Philippe Derreumaux and Valleix, Sophie} }