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HUMAN GELSOLIN FROM RESIDUES GLU28 TO ARG161 WITH CALCIUM
Structural highlights
DiseaseGELS_HUMAN Defects in GSN are the cause of amyloidosis type 5 (AMYL5) [MIM:105120; also known as familial amyloidosis Finnish type. AMYL5 is a hereditary generalized amyloidosis due to gelsolin amyloid deposition. It is typically characterized by cranial neuropathy and lattice corneal dystrophy. Most patients have modest involvement of internal organs, but severe systemic disease can develop in some individuals causing peripheral polyneuropathy, amyloid cardiomyopathy, and nephrotic syndrome leading to renal failure.[1] [2] [3] [4] FunctionGELS_HUMAN Calcium-regulated, actin-modulating protein that binds to the plus (or barbed) ends of actin monomers or filaments, preventing monomer exchange (end-blocking or capping). It can promote the assembly of monomers into filaments (nucleation) as well as sever filaments already formed. Plays a role in ciliogenesis.[5] Publication Abstract from PubMedHere, we report that minimal functional gelsolin i.e. fragment 28-161 can display F-actin depolymerizing property even after heating the protein to 80 degrees C. Small angle X-ray scattering (SAXS) data analysis confirmed that under Ca(2+)-free conditions, 28-161 associates into monomer to dimer and tetramer, which later forms beta-amyloids, but in presence of Ca(2+), it forms dimers which proceed to non-characterizable aggregates. The dimeric association also explained the observed decrease in ellipticity in circular dichroism experiments with increase in temperature. Importantly, SAXS data based models correlated well with our crystal structure of dimeric state of 28-161. Characterization of higher order association by electron microscopy, Congo red and ThioflavinT staining assays further confirmed that only in absence of Ca(2+) ions, heating transforms 28-161 into beta-amyloids. Gel filtration and other experiments showed that beta-amyloids keep leaching out the monomer, and the release rates could be enhanced by addition of L-Arg to the amyloids. F-actin depolymerization showed that addition of Ca(2+) ions to released monomer initiated the depolymerization activity. Overall, we propose a way to compose a supramolecular assembly which releases functional protein in sustained manner which can be applied for varied potentially therapeutic interventions. Bonsai Gelsolin Survives Heat Induced Denaturation by Forming beta-Amyloids which Leach Out Functional Monomer.,Badmalia MD, Sharma P, Yadav SPS, Singh S, Khatri N, Garg R, Ashish Sci Rep. 2018 Aug 22;8(1):12602. doi: 10.1038/s41598-018-30951-3. PMID:30135452[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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