Sea star tenacity mediated by a protein that fragments, then aggregates

Abstract

Sea stars adhere firmly but temporarily to various substrata as a result of underwater efficient adhesive secretions released by their tube feet. Previous studies showed that this material is mainly made up of proteins, which play a key role in its adhesiveness and cohesiveness. Recently, we solubilized the majority of these proteins and obtained 43 de novo-generated peptide sequences by tandem MS. Here, one of these sequences served to recover the full-length sequence of Sea star footprint protein 1 (Sfp1), by RT-PCR and tube foot transcriptome analysis. Sfp1, a large protein of 3,853 aa, is the second most abundant constituent of the secreted adhesive. By using MS and Western blot analyses, we showed that Sfp1 is translated from a single mRNA and then cleaved into four subunits linked together by disulphide bridges in tube foot adhesive cells. The four subunits display specific protein-, carbohydrate-, and metal-binding domains. Immunohistochemistry and immunocytochemistry located Sfp1 in granules stockpiled by one of the two types of adhesive cells responsible for the secretion of the adhesive material. We also demonstrated that Sfp1 makes up the structural scaffold of the adhesive footprint that remains on the substratum after tube foot detachment. Taken together, the results suggest that Sfp1 is a major structural protein involved in footprint cohesion and possibly in adhesive interactions with the tube foot surface. In recombinant form, it could be used for the design of novel sea starinspired biomaterials.echinoderms | Asterias rubens | marine adhesion

Mussel adhesion – essential footwork

“…As many of these steps appear to be adaptations to accommodate and regulate the reactivity of Dopa, one must ask why any organism would rely on an adhesive with such high management costs. Other organisms such as barnacles and sea stars have evolved perfectly good Dopa-less adhesives (Kamino, 2013;Hennebert et al, 2014). Perhaps investment in Dopa is related to its versatility, e.g.…”

An integrated transcriptomic and proteomic analysis of sea star epidermal secretions identifies proteins involved in defense and adhesion

“…A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT 14 of them matching to the sea urchin Strongylocentrotus purpuratus, which is the only echinoderm species for which the whole sequenced and annotated genome [32] is available in public databases, 15% matching to the acorn worm Saccoglossus kowalevskii, and the remaining matching to other species (including the sea star Solaster dawsoni). Based on SignalP and SecretomeP analyses, 80% of the annotated proteins were inferred to contain a secretion signal (supplemental Table S3a).…”

“…These domains are known from other studies to mediate protein-protein, proteincarbohydrate, or protein-metal interactions [44][45][46]. Such domains could therefore provide cohesive and adhesive interactions between sea star footprint proteins and other glycans and/or proteins present in the adhesive material and in the outermost layer of the cuticle covering the tube foot epidermis, respectively [11,14,47]. Indeed, some of them have already been highlighted in Sfp1, the first adhesive protein characterized so far in sea stars [14].…”

“…A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT 5 for navies) or in the field of medicine and dentistry [13,14]. The complete sequence of one sea star adhesive protein, Sfp1, has recently been obtained in Asterias rubens [14].…”

“…The complete sequence of one sea star adhesive protein, Sfp1, has recently been obtained in Asterias rubens [14]. This large protein of 426 kDa displays specific protein-, carbohydrate-and metal-binding domains that could contribute to the cohesion of the adhesive footprint as well as to adhesive interactions between the footprint and the cuticle covering the tube foot epithelium [14]. Other potential novel adhesive proteins have been highlighted but no complete sequence is available yet for them [15].…”