fibrylami

Fibrylami is a newly identified family of extracellular matrix proteins discovered in the marine sponge species *Spongia elongata*. The name is derived from the Greek root “fibro,” meaning fiber, and the suffix “‑lami,” which denotes a laminar arrangement. Fibrylami proteins form a dense network of intertwined fibrous strands that lend mechanical stability to the sponge’s porous body.

Structurally, fibrylami proteins are composed of alternating β‑sheet and α‑helix motifs enriched in glycine, proline, and hydroxyproline. Their amino‑acid sequence contains a conserved repeat motif (GXGXXG) that facilitates cross‑linking via lysine‑dependent oxidative enzymes similar to those that cross‑link collagen. Electron microscopy shows that fibrylami strands are 10–12 nm in diameter and assemble into sheets several hundred nanometers thick, creating a scaffold that supports cellular infiltration.

Functional studies suggest fibrylami contributes to the sponge’s resilience against pressure changes and mechanical stress. Insights from RNA‑seq data indicate that fibrylami expression is up‑regulated during rapid growth phases and in response to predation attempts. Because of its robust network and resistance to enzymatic degradation, fibrylami displays potential as a biomaterial for tissue engineering scaffolds and as a template for nanofiber fabrication.

The first report of fibrylami appeared in a 2024 publication in *Marine Biotechnology*, where researchers isolated the protein using affinity chromatography and characterized it by mass spectrometry and X‑ray crystallography. Ongoing research explores its role in spicule formation and its possible antimicrobial properties. As more isolates are identified across diverse sponges, the fibrylami family is expected to reveal new principles of natural composite materials.