A secreted LEA-like protein functions as a basement membrane stress protectant

Organisms have evolved to withstand a wide variety of environmental stresses. Survival requires individual cells to mount appropriate responses to combat molecular damage. In animals, multicellularity introduces an additional challenge: how is tissue integrity preserved? Our knowledge of extracellular tissue-level mechanisms of protection remains limited. Here, we report that a late embryogenesis abundant (LEA)-like protein, DUR-1, is secreted and then accumulates in basement membranes, where it acts to promote tissue integrity and stress survival. DUR-1 is strongly upregulated in the stress-tolerant dauer diapause stage of C. elegans and further upregulated upon desiccation. Loss of the protein sensitizes animals to desiccation and osmotic stress. Other LEA proteins have been regarded as strong desicco-protectants, but none have been recognized as components of basement membranes. We show that DUR-1 is important for maintaining the integrity of basement membrane-ensheathed tissues under mechanical stresses associated with drying or osmotic challenge. This work defines a mechanism for extracellular protection and emphasizes the importance of preserving tissue integrity during stress.