The Role of the Prod1 Membrane Anchor in Newt Limb Regeneration.

Prod1 is a protein that regulates limb regeneration in salamanders by determining the direction of limb growth. Prod1 is attached to the membrane by a glycosylphosphatidylinositol (GPI) anchor, but the role of membrane anchoring in the limb regeneration process is poorly understood. In this study, we investigated the functional role of the anchoring of Prod1 to the membrane by using its synthetic mimics in combination with solid-state NMR spectroscopy and fluorescent microscopy techniques. Anchoring did not affect the three-dimensional structure of Prod1 but did induce aggregation by aligning the molecules and drastically reducing the molecular motion on the two-dimensional membrane surface. Interestingly, aggregated Prod1 interacted with Prod1 molecules tethered on the surface of opposing membranes, inducing membrane adhesion. Our results strongly suggest that anchoring of the salamander-specific protein Prod1 assists cell adhesion in the limb regeneration process.