Activation of neuron adhesion and neurite extension by tethered neurotrophins and adhesion molecules

Abstract

Laminin, neural cell adhesion molecule (N-CAM) and the neurotrophins, ciliary neurotrophic factor (CNTF) and brain-derived neurotrophic factor (BDNF) play important roles in the formation and maintenance of the axons and dendrites of vertebrate neurons. The conventional explanation of the action of N-CAM and laminin has been that they provide suitable substrata on which the cells can adhere, spread and extend. We show by applying these molecules immobilised to small beads (tethered) that they activate adhesion and cell extension on substrata where no special adhesion molecules have been placed. This activation occurs even when the beads are attached to the side of the cell not in contact with the substratum, implying that the signal is transduced to activate parts of the cell remote from the vicinity of the bead.