Native chick laminin-4 containing the beta 2 chain (s-laminin) promotes motor axon growth.
After denervation of muscle, motor axons reinnervate original synaptic sites. A recombinant fragment of the synapse specific laminin beta 2 chain (s-laminin) was reported to inhibit motor axon growth. Consequently, a specific sequence (leucine-arginine-glutamate, LRE) of the laminin beta 2 chain was proposed to act as a stop signal and to mediate specific reinnervation at the neuromuscular junction (Porter, B.E., J. Weis, and J.R. Sanes. 1995. Neuron. 14:549-559). We demonstrate here that native chick laminin-4, which contains the beta 2 chain and is present in the synaptic basement membrane, does not inhibit but rather promotes motor axon growth. In native heterotrimeric laminin, the LRE sequence of the beta 2 chain is found in a triple coiled-coil region that is formed by all three subunits. We show here that the effect of LRE depends on the structural context. Whereas a recombinant randomly coiled LRE peptide indeed inhibited outgrowth by chick motoneurons, a small recombinant triple coiled-coil protein containing this sequence did not.
Brandenberger
R
R
Department of Biophysical Chemistry, Biocenter, University of Basel, Switzerland.
Kammerer
R A
RA
Engel
J
J
Chiquet
M
M
D000595:Amino Acid Sequence; D000818:Animals; D001369:Axons / Q000502:physiology*; D002455:Cell Division / Q000235:genetics / Q000502:physiology; D002478:Cells, Cultured; D002642:Chick Embryo; D003470:Culture Media; D007797:Laminin / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D051379:Mice; D008969:Molecular Sequence Data; D009046:Motor Neurons / Q000502:physiology*; D016501:Neurites / Q000502:physiology; D011401:Promoter Regions, Genetic; D011487:Protein Conformation
D003470:Culture Media; D007797:Laminin; C058783:laminin beta2