Spectrin-actin interaction is required for neurite extension in NB 2a/dl neuroblastoma cells.
Spectrin is an actin-binding membrane skeleton protein involved in the maintenance of cell shape and generation of distinct membrane protein domains. Actin binds to the N-terminal domain of beta-spectrin. To examine the function of spectrin-actin interaction in neurons, we sought to disrupt this interaction in differentiating NB 2a neuroblastoma cells by microinjecting an N-terminal domain-specific anti-beta-spectrin antibody. We found that microinjection of the affinity-purified N-terminal domain-specific anti-beta-spectrin inhibited the extension of the neurites in NB 2a/dl cells. The microinjected cells remained flat, and put out many filopodia-like processes; but these processes failed to extend when the cells were induced to differentiate in the presence of dbc AMP or in serum-free medium. The N-terminal domain-specific anti-beta-spectrin also inhibited the binding of spectrin to actin. By contrast, the microinjection of monospecific anti-alpha-spectrin(G) did not inhibit neurite extension. These results suggest that beta-spectrin-actin interaction may be required for neurite extension, which is critical for development of polarity in nerve cells.
Sihag
R K
RK
Department of Psychiatry, Harvard Medical School, McLean Hospital, Belmont, Massachusetts 02178, USA.
Shea
T B
TB
Wang
F S
FS
D000199:Actins / Q000502:physiology*; D000818:Animals; D002478:Cells, Cultured / Q000502:physiology; D004586:Electrophoresis; D007150:Immunohistochemistry; D051379:Mice; D008815:Mice, Inbred Strains; D016501:Neurites / Q000502:physiology*; D009447:Neuroblastoma / Q000378:metabolism*; D013049:Spectrin / Q000502:physiology*
D000199:Actins; D013049:Spectrin