Motor, sensory and autonomic nerve terminals containing NAP-22 immunoreactivity in the rat muscle.
Neuron-enriched acidic protein having a molecular mass of 22 kDa, NAP-22, is a Ca(2+)-dependent calmodulin-binding protein and is phosphorylated with protein kinase C (PKC). This protein is localized to the biological membrane via myristoylation and found in the membrane fraction of the brain and in the synaptic vesicle fraction. Recent studies showed that NAP-22 is localized in the membrane raft domain in a cholesterol-dependent manner and suggest a role for NAP-22 in maturation and/or maintenance of nerve terminals by controlling cholesterol-dependent membrane dynamics. The present study revealed the immunohistochemical distribution of NAP-22 in the peripheral nerves in rat muscles. In all examined muscles, nerve terminals in the motor endplates showed NAP-22 immunoreactivity associated with the membranes of synaptic vesicles and nerve terminals. In the muscle spindles, annulospiral endings, which made spirals around the intrafusal muscles, showed intense NAP-22 immunoreactivity. Autonomic nerve fibers around the intramuscular blood vessels also showed the immunoreactivity for NAP-22. NAP-22 immunoreactivity in these peripheral nerves was observed from birth to adulthood (100 days after birth). Though growth-associated protein-43 (GAP-43) immunoreactivity in these nerves was observed from birth, this immunoreactivity decreased from 20 days after birth. These findings suggest that NAP-22 is distributed and regulates functions in the motor, sensory and autonomic nerve terminals in the peripheral nervous system.
Iino
Satoshi
S
Department of Anatomy, University of Fukui Faculty of Medical Science, Matsuoka, Fukui 910-1193, Japan. iinosa@fmsrsa.fukui-med.ac.jp
Taguchi
Katsutoshi
K
Maekawa
Shohei
S
Nojyo
Yoshiaki
Y
D000818:Animals; D017776:Autonomic Pathways / Q000737:chemistry* / Q000254:growth & development; D002148:Calmodulin-Binding Proteins / Q000032:analysis*; D003598:Cytoskeletal Proteins; D005260:Female; D008297:Male; D009046:Motor Neurons / Q000737:chemistry* / Q000502:physiology; D009470:Muscle Spindles / Q000737:chemistry* / Q000254:growth & development; D009419:Nerve Tissue Proteins / Q000032:analysis*; D009475:Neurons, Afferent / Q000737:chemistry* / Q000502:physiology; D017729:Presynaptic Terminals / Q000737:chemistry / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley
D002148:Calmodulin-Binding Proteins; D003598:Cytoskeletal Proteins; D009419:Nerve Tissue Proteins; C066853:Basp1 protein, rat