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Time‐Dependent Increase in Protein Phosphorylation Following One‐Trial Enhancement in Hermissenda
Author(s) -
Crow Terry,
Siddiqi Vilma,
Zhu Qing,
Neary Joseph T.
Publication year - 1996
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.1996.66041736.x
Subject(s) - phosphorylation , neuroscience , protein phosphorylation , chemistry , biochemistry , biology , protein kinase a
One‐trial conditioning of the nudibranch mollusk Hermissenda produces short‐ and long‐term changes in excitability (enhancement) of identified sensory neurons. To investigate the biochemical mechanisms underlying this example of plasticity, we have examined changes in protein phosphorylation at different times following the in vitro conditioning trial. Changes in the incorporation of 32 PO 4 into proteins were determined using two‐dimensional polyacrylamide gel electrophoresis, autoradiography, and densitometry. Conditioning resulted in increases in levels of several phosphoproteins, five of which, ranging in apparent molecular mass from 22 to 55 kDa, were chosen for analysis. The increased phosphorylation of the 46‐ and 55‐kDa phosphoproteins detected 2 h postconditioning was significantly greater than the level of phosphorylation detected in an unpaired control group, indicating that long‐term enhancement is pairing specific. Statistically significant increases in phosphorylation as compared with the control group that received only light were detected immediately after conditioning (5 min) for the 55‐, 46‐, and 22‐kDa phosphoproteins, at 1 h for the 55‐ and 46‐kDa phosphoproteins, and at 2 h for the 55‐, 46‐, and 22‐kDa phosphoproteins. The 46‐ and 55‐kDa phosphoproteins are putative structural proteins, and the 22‐kDa phosphoprotein is proposed to be a protein kinase C substrate previously identified in Hermissenda following multitrial classical conditioning. Time‐dependent increases in protein phosphorylation may contribute to the induction and maintenance of different memory stages expressed in sensory neurons after one‐trial conditioning.