J. Biol. Chem., Vol. 268, Issue 35, 26260-26267, 12, 1993
Functional characterization of beta isoforms of murine Na,K-ATPase. The adhesion molecule on glia (AMOG/beta 2), but not beta 1, promotes neurite outgrowth
G Muller-Husmann, S Gloor and M Schachner
Department of Neurobiology, Swiss Federal Institute of Technology, Zurich.
We have previously provided evidence for a dual function of the adhesion
molecule on glia (AMOG/beta 2), the beta 2 subunit of the murine
Na,K-ATPase, both as neural recognition molecule mediating neuron-glia
interactions and as functional beta subunit of the sodium pump. To analyze
the functional role of AMOG/beta 2 in neurite outgrowth, AMOG/beta
2-expressing L-cells were generated by transfection and used as substrates
for neurite outgrowth of cerebellar and hippocampal neurons. AMOG/beta
2-transfected L-cells led to an increase in neurite length after 6 h, which
was specifically inhibited by antibodies to AMOG/beta 2 and a neuronal
membrane fraction. Moreover, the extracellular domain of AMOG/beta 2
generated as a soluble recombinant protein in Chinese hamster ovary cells
partially inhibited the increase in neurite outgrowth on AMOG/beta
2-transfected L-cells. L-cells transfected with the mouse beta 1 subunit
had no effect on neurite extension. Our observations show for the first
time differences in functional properties for different beta isoforms of
the Na,K-ATPase and suggest that AMOG/beta 2 but not beta 1 is able to
interact with an unknown neuronal receptor leading to increased neurite
outgrowth, most likely via signal transduction.