Newly identified protein complex sheds light on axon growth mechanism

New research sheds light on the molecular mechanisms underlying axon growth and synapse formation in the nematode worm C.elegans. In a study published today in the open access journal Journal of Biology, researchers have characterised a new protein, UNC-69, required for proper locomotion . They show that UNC-69 interacts with UNC-76 in a protein complex likely to be involved in the trafficking of vesicles along axons - a process that drives axon growth and helps synapse formation. The research also shows that UNC-69 is directly involved in the formation of new synapses.

A group led by Michael Hengartner, from the University of Zurich in Switzerland, cloned and characterised UNC-69, a previously known protein that had never been characterised. By studying mutants lacking unc-69 they show that the protein is widely expressed in the C.elegans nervous system and is required for normal axon development.

Hengartner and colleagues then show that UNC-69 physically interacts with another protein expressed in the nervous system, UNC-76. Through experiments on double mutant combinations, the authors show that the two proteins cooperate to regulate axon development. The authors also show that UNC-69 is needed for the formation or maintenance of new synapses.

It is known that UNC-76 binds to molecular 'motor' proteins called kinesins that transport vesicles along growing axons. Hengartner and colleagues propose that the UNC-69/UNC-76 complex may be implicated in vesicle trafficking, a process that is necessary for axon growth and new synapse formation.

The short coiled-coil domain-containing protein UNC-69 cooperates with UNC-76 to regulate axonal outgrowth and normal presynaptic organization in Caenorhabditis elegans
Cheng-Wen Su, Suzanne Tharin, Yishi Jin, Bruce Wightman, Mona Spector, David Meili, Nancy Tsung, Christa Rhiner, Dimitris Bourikas, Esther Stoeckli, Gian Garriga, H Robert Horvitz and Michael O Hengartner
Journal of Biology 2006, 5:9 (25 May 2006)

Source : BioMed Central