Longer Duct, Better Silk: Unveiling How Anterior Silk Gland Length Boosts Fiber Performance

The mechanical performance of silk is closely tied to
the fibrillization
process within the anterior segment of silk gland (ASG). While a long
and narrow ASG is conserved across silk-spinning species, its biological
role remains unclear. Here, we performed a comprehensive structure–function
analysis of the silkworm ASG and revealed that its long and narrow
morphology plays an essential role in silk fibrillization and fiber
performance. A steep reduction in duct diameter at the ASG’s
onset initiates silk protein transformation, while the extended duct
length promotes molecular alignment, crystallization, and orientation.
Genetic manipulation to extend ASG length significantly increased
the Young’s modulus and toughness of silkworm silk fibers.
These findings demonstrate the potential of ASG length modulation
as an effective strategy to improve silk fiber performance and provide
valuable insights into the biological and functional importance of
silk gland morphology.