[GELS_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.
[GELS_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.
Gelsolin is a calcium and pH-sensitive modulator of actin filament length. Here, we use X-ray crystallography to examine the extraction and exchange of calcium ions from their binding sites in different crystalline forms of the activated N and C-terminal halves of gelsolin, G1-G3 and G4-G6, respectively. We demonstrate that the combination of calcium and low pH activating conditions do not induce conformational changes in G4-G6 beyond those elicited by calcium alone. EGTA is able to remove calcium ions bound to the type I and type II metal ion-binding sites in G4-G6. Constrained by crystal contacts and stabilized by interdomain interaction surfaces, the gross structure of calcium-depleted G4-G6 remains that of the activated form. However, high-resolution details of changes in the ion-binding sites may represent the initial steps toward restoration of the arrangement of domains found in the calcium-free inactive form of gelsolin in solution. Furthermore, bathing crystals with the trivalent calcium ion mimic, Tb3+, results in anomalous scattering data that permit unequivocal localization of terbium ions in each of the proposed type I and type II ion-binding sites of both halves of gelsolin. In contrast to predictions based on solution studies, we find that no calcium ion is immune to exchange.
Calcium ion exchange in crystalline gelsolin.,Chumnarnsilpa S, Loonchanta A, Xue B, Choe H, Urosev D, Wang H, Lindberg U, Burtnick LD, Robinson RC J Mol Biol. 2006 Mar 31;357(3):773-82. Epub 2006 Jan 26. PMID:16466744
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↑ Maury CP, Alli K, Baumann M. Finnish hereditary amyloidosis. Amino acid sequence homology between the amyloid fibril protein and human plasma gelsoline. FEBS Lett. 1990 Jan 15;260(1):85-7. PMID:2153578
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↑ de la Chapelle A, Tolvanen R, Boysen G, Santavy J, Bleeker-Wagemakers L, Maury CP, Kere J. Gelsolin-derived familial amyloidosis caused by asparagine or tyrosine substitution for aspartic acid at residue 187. Nat Genet. 1992 Oct;2(2):157-60. PMID:1338910 doi:http://dx.doi.org/10.1038/ng1092-157
↑ Kim J, Lee JE, Heynen-Genel S, Suyama E, Ono K, Lee K, Ideker T, Aza-Blanc P, Gleeson JG. Functional genomic screen for modulators of ciliogenesis and cilium length. Nature. 2010 Apr 15;464(7291):1048-51. doi: 10.1038/nature08895. PMID:20393563 doi:10.1038/nature08895
↑ Chumnarnsilpa S, Loonchanta A, Xue B, Choe H, Urosev D, Wang H, Lindberg U, Burtnick LD, Robinson RC. Calcium ion exchange in crystalline gelsolin. J Mol Biol. 2006 Mar 31;357(3):773-82. Epub 2006 Jan 26. PMID:16466744 doi:10.1016/j.jmb.2006.01.026