Isolation of a G protein that is modified by learning and reduces potassium currents in Hermissenda.
In Hermissenda crassicornis conditioned to associate light and rotation, type B photoreceptor neurons exhibit pairing-specific decreases in the potassium currents IA and IK-Ca, which account for many of the behavioral changes elicited by associative conditioning. To determine which proteins are involved in storage of this memory, high-performance liquid chromatography was used to examine proteins from Hermissenda eyes. Conditioning-specific changes in four phosphoproteins were observed 24 hours after conditioning. One of these proteins, cp20, was purified to apparent homogeneity and found to be a G protein. When injected back into Hermissenda type B cells, cp20 reduced IK and IK-Ca in a manner indistinguishable from the reduction caused by conditioning, suggesting that this protein may play a crucial role in memory acquisition or retention.
Nelson
T J
TJ
Laboratory of Molecular and Cellular Neurobiology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892.
Collin
C
C
Alkon
D L
DL
D000818:Animals; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D003213:Conditioning, Psychological / Q000502:physiology; D005136:Eye Proteins / Q000302:isolation & purification / Q000502:physiology; D019204:GTP-Binding Proteins / Q000302:isolation & purification* / Q000502:physiology; D007858:Learning / Q000502:physiology; D008974:Mollusca / Q000378:metabolism*; D010750:Phosphoproteins / Q000302:isolation & purification / Q000502:physiology; D011188:Potassium / Q000378:metabolism*; D015221:Potassium Channels / Q000502:physiology
D005136:Eye Proteins; D010750:Phosphoproteins; D015221:Potassium Channels; D019204:GTP-Binding Proteins; D011188:Potassium