Collagen’s enigmatic, highly conserved <i>N</i> -glycan has an essential proteostatic function
Rasia C. Li, Madeline Wong, Andrew S. DiChiara, Azade S. Hosseini, Matthew D. Shoulders
Abstract
Significance Development and repair of connective tissues require the rapid biosynthesis of large quantities of collagen, the most abundant protein in the human body. The functional importance of collagen has motivated extensive efforts to uncover molecular mechanisms responsible for matching collagen production to physiological needs. While many roles for collagen chaperones and modifying enzymes are well established, the function of the highly conserved N -glycosylation site within collagen’s C-terminal globular domain has remained elusive for decades. By assaying N -glycan function under conditions of impaired collagen folding, we show that, although the N -glycan is dispensable under normal conditions, it is essential for collagen folding and secretion under conditions that challenge proteostasis. Such environments are commonly encountered during development, tissue repair, and disease.