The Journal of Neuroscience, December 15, 2002, 22(24):10514-10518
BRIEF COMMUNICATION
One-Trial In Vitro Conditioning Regulates a
Cytoskeletal-Related Protein (CSP24) in the Conditioned Stimulus
Pathway of Hermissenda
Terry
Crow and
J. J.
Xue-Bian
Department of Neurobiology and Anatomy, University of Texas Medical
School, Houston, Texas 77225
Hermissenda CSP24 (cytoskeletal-related protein
24) is a 24 kDa
-thymosin-like protein that is associated
with intermediate memory. We showed previously that one-trial
conditioning resulted in a significant increase in the phosphorylation
of CSP24 detected in lysates of the pathway supporting the conditioned
stimulus (CS). Here we report the association of the protein with the
actin cytoskeleton and the distribution of CSP24-immunoreactive neurons in two sensory structures and the circumesophageal nervous system. Identified photoreceptors, hair cells, and neurons in the
cerebropleural and pedal ganglia were immunoreactive for CSP24.
Immunoprecipitation experiments with
32PO4-labeled lysates of the circumesophageal
nervous system identified a 44 kDa protein band (consistent with actin)
that coprecipitates with CSP24. An analysis of immunoprecipitates on
Western blots probed with anti-actin antibody also showed that actin
coprecipitates with CSP24. Laser confocal microscopy of photoreceptors
costained with fluorescently labeled anti-actin antibody and anti-CSP24 antibody, or fluorescent phalloidin and anti-CSP24 antibody showed that
CSP24 is localized with actin in the cytosol of photoreceptor cell
bodies and colocalized with presumed G-actin, but not F-actin, in
regions adjacent to the plasma membrane. Although CSP24 is widely
distributed in the Hermissenda nervous system, its
regulation by one-trial conditioning was observed only in the CS
pathway. Our findings suggest that CSP24 may interact with components
of the actin cytoskeleton that contribute to structural changes
underlying the formation and maintenance of enduring forms of memory.
Key words:
Hermissenda; pavlovian conditioning; cytoskeleton; actin; phosphorylation;
-thymosin repeat protein
Copyright © 2002 Society for Neuroscience 0270-6474/02/222410514-05$05.00/0