Multi-omics reveal spider silk fiber composition

Spider major ampullate silk fiber, which is used as a safety line, is renowned for its remarkable strength and flexibility, yet the exact mechanisms behind its production remain largely unknown.

A new study by Anna Rising’s lab with the support from NBIS expert Johan Reimegård has provided novel insights into the production and composition of this fascinating material. By employing advanced sequencing techniques, the spider’s silk-producing gland was characterized at the cellular level, revealing that the gland is composed of six different cell types, each confined to one of three distinct zones. They also identified that the silk fiber is primarily composed of 18 different proteins, including some previously unknown proteins. Furthermore, the proteins secreted by the cells in the three zones are not mixed in the gland but remain as layers that persist in the fiber. This means that the major ampullate fiber consists of three layers of protein mixtures, resembling concentric cylinders, which differ significantly in composition. This knowledge is crucial for advancing the development of artificial spider silk with properties that mirror those of the natural fiber. It also provides insight into how nature has elegantly solved the challenges of spinning an exceptionally tough fiber from a protein solution.

The project is financed by the Olle Engkvist Foundation, Formas and the European Research Council (ERC Consolidator Grant) and carried out at the Swedish University of Agricultural Sciences, Karolinska Institutet, and National Bioinformatics Infrastructure Sweden/Science for Life Laboratory.

Paper in Science Advances: https://www.science.org/doi/10.1126/sciadv.adn0597

News stories in Swedish media:

https://www.svt.se/nyheter/vetenskap/ny-upptackt-sa-spinner-spindeln-sitt-starka-nat

https://www.aftonbladet.se/nyheter/a/0VBzbJ/studie-ett-steg-narmare-konstgjord-spindeltrad