Ezrin immunoreactivity in neuron subpopulations: cellular distribution in relation to cytoskeletal proteins in sensory neurons.
Ezrin was first identified as a low-abundance phosphoprotein associated with the cytoskeletal core of microvilli, where it may function as a regulatory protein. We report immunocytochemical evidence for expression of ezrin, or an ezrin-like protein of molecular mass near 80 KD, confined to select populations of neurons, including sensory, motor, and autonomic, during chick embryonic development. We have compared the distribution of anti-ezrin staining with that of other major cytoskeletal proteins in sensory neurons in an effort to identify a possible association of the neural homologue of ezrin with the neuronal cytoskeleton. The diffuse distribution of anti-ezrin staining in the cell soma bore little resemblance to the filamentous staining observed with antibodies to the 68 KD neurofilament protein and alpha-tubulin. F-actin staining with fluorescein-conjugated phalloidin was indistinguishable from the anti-ezrin staining pattern in the soma of cultured neurons, including a peak in staining intensity around the periphery of the cell. Microfilaments in growth cones did not stain with the ezrin antibody. A close correspondence between the anti-ezrin and anti-spectrin staining patterns was found on cryostat sections of dorsal root ganglia, but the anti-spectrin staining was weak and could not be demonstrated in culture. Our findings, primarily from cultured neurons, are not inconsistent with ezrin associating with F-actin, although not with microfilaments found in motile structures such as growth cones.
Everett
A W
AW
Neurobiology Research Centre, University of Sydney, NSW, Australia.
Nichol
K A
KA
D000199:Actins / Q000032:analysis; D000818:Animals; D000911:Antibodies, Monoclonal; D002642:Chick Embryo; D003598:Cytoskeletal Proteins / Q000032:analysis*; D005455:Fluorescent Antibody Technique; D005727:Ganglia, Spinal / Q000032:analysis / Q000196:embryology; D006651:Histocytochemistry; D015151:Immunoblotting; D007381:Intermediate Filament Proteins / Q000032:analysis; D051379:Mice; D008807:Mice, Inbred BALB C; D008970:Molecular Weight; D016900:Neurofilament Proteins; D009474:Neurons / Q000032:analysis*; D009475:Neurons, Afferent / Q000032:analysis*; D010750:Phosphoproteins / Q000032:analysis*; D013049:Spectrin / Q000032:analysis; D014404:Tubulin / Q000032:analysis; D000099149:Ezrin
D000199:Actins; D000911:Antibodies, Monoclonal; D003598:Cytoskeletal Proteins; D007381:Intermediate Filament Proteins; D016900:Neurofilament Proteins; D010750:Phosphoproteins; D013049:Spectrin; D014404:Tubulin; D000099149:Ezrin