Primary cilium serves as “cellular GPS” in wound repair and beyond

18 December 2008

If cells held high school reunions, the primary cilium would be the class nerd who comes back in glory as a bioscience millionaire. Once written off as a vestigial organelle left in the evolutionary dust, the primary cilium has in the last decade risen to prominence as a vital cellular sensor at the root of everything from polycystic kidney disease to cancer to left–right anatomical abnormalities.

Now comes evidence that the primary cilium may act as a “cellular GPS,” orienting cells that play a critical role in wound healing to move in the right direction. Søren T. Christensen and colleagues at the University of Copenhagen in Denmark and the Albert Einstein College of Medicine in the Bronx have discovered that the primary cilia of cultured fibroblasts are oriented to detect a growth factor signal critical to efficient wound closure. When properly stimulated, the primary cilia steer fibroblast cells toward the wound. Furthermore, mice with engineered defects in the formation of primary cilia show a reduced rate of wound repair and have defects in wound closure.

“The really important discovery is that the primary cilium detects signals, which tell the cells to engage their compass reading and move in the right direction to close the wound,” Christensen explains. The primary cilia are solitary, antenna-like structures that protrude through the membrane from a centrosome at the cell surface. Primary cilia are found on almost every nondividing cell in the body.

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