Twigs into branches: how a filopodium becomes a dendrite.
A dendrite grows by sprouting filopodia, some of which mature into stable dendrite branches that bear synapses and sprout filopodia of their own. Recent work has shown that a filopodium begins deciding to become a stable branch within 1min of contacting a presynaptic partner, but what triggers this decision remains unknown. We consider the evidence for three possible triggers: activity of neurotransmitter receptors, signaling through adhesion proteins, and heightened membrane tension as the filopodium attempts to retract but is held in place by adhesive contacts with the target. Of these, membrane tension-induced signaling is especially appealing, as it would serve as a general reporter of attachment, independent of which specific adhesion molecules are used.
Heiman
Maxwell G
MG
Laboratory of Developmental Genetics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA. heiman@rockefeller.edu
Shaham
Shai
S
D000818:Animals; D002118:Calcium / Q000378:metabolism; D002448:Cell Adhesion / Q000502:physiology; D002462:Cell Membrane / Q000502:physiology; D003712:Dendrites / Q000502:physiology*; D011554:Pseudopodia / Q000502:physiology*; D013569:Synapses / Q000502:physiology*; D009435:Synaptic Transmission / Q000502:physiology
D002118:Calcium