Silicanin-1 is a conserved diatom membrane protein involved in silica biomineralizationReportar como inadecuado

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BMC Biology

, 15:65

First Online: 24 July 2017Received: 18 May 2017Accepted: 28 June 2017


BackgroundBiological mineral formation biomineralization proceeds in specialized compartments often bounded by a lipid bilayer membrane. Currently, the role of membranes in biomineralization is hardly understood.

ResultsInvestigating biomineralization of SiO2 silica in diatoms we identified Silicanin-1 Sin1 as a conserved diatom membrane protein present in silica deposition vesicles SDVs of Thalassiosira pseudonana. Fluorescence microscopy of GFP-tagged Sin1 enabled, for the first time, to follow the intracellular locations of a biomineralization protein during silica biogenesis in vivo. The analysis revealed incorporation of the N-terminal domain of Sin1 into the biosilica via association with the organic matrix inside the SDVs. In vitro experiments showed that the recombinant N-terminal domain of Sin1 undergoes pH-triggered assembly into large clusters, and promotes silica formation by synergistic interaction with long-chain polyamines.

ConclusionsSin1 is the first identified SDV transmembrane protein, and is highly conserved throughout the diatom realm, which suggests a fundamental role in the biomineralization of diatom silica. Through interaction with long-chain polyamines, Sin1 could serve as a molecular link by which the SDV membrane exerts control on the assembly of biosilica-forming organic matrices in the SDV lumen.

KeywordsDiatom biosilica Biomineralization vesicles Transmembrane protein Vesicle biogenesis Exocytosis Time-lapse confocal fluorescence microscopy Protein self-assembly Cryo-TEM Silica formation activity AbbreviationsBLASTbasic local alignment search tool

DLSdynamic light scattering

EASWenriched artificial sea water

EDTAethylenediamine tetraacetic acid

GFPenhanced green fluorescent protein

LCPAlong-chain polyamines

MMETSPMarine Microbial Eukaryote Transcriptome Sequencing Project

MREmean residue ellipticity


PAGEpolyacrylamide gel electrophoresis


SDSSodium dodecylsulfate

SDVsilica deposition vesicle



Electronic supplementary materialThe online version of this article doi:10.1186-s12915-017-0400-8 contains supplementary material, which is available to authorized users.

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Autor: Alexander Kotzsch - Philip Gröger - Damian Pawolski - Paul H. H. Bomans - Nico A. J. M. Sommerdijk - Michael Schlierf


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