Identification of three proteins in the eye of Aplysia, whose synthesis is altered by serotonin (5-HT). Possible involvement of these proteins in the ocular circadian system.
Previous results using translation inhibitors in the ocular circadian system of Aplysia suggest that protein synthesis may be involved in the light and serotonin (5-HT) entrainment pathways or perhaps in the circadian oscillator. Proteins have been previously identified whose synthesis was altered by treatments of light capable of perturbing the phase of the circadian rhythm in the eye of Aplysia. We extended these studies by investigating the effects of other treatments that perturb the ocular circadian rhythm on protein synthesis. 5-HT altered the synthesis of nine proteins. Interestingly, five of the proteins affected by treatments with 5-HT were previously shown to be affected by treatments with light. Four of the proteins affected by treatments with 5-HT were also affected by treatments with analogs of cAMP, a treatment which mimics the effects of 5-HT on the ocular circadian rhythm. To identify the cellular function of some of these proteins, we obtained their partial amino acid sequences. Based on these sequences and additional characterizations, a 78-kDa, pI 5.6 Aplysia protein appears to be glucose-regulated protein 78/binding protein, and a 36-kDa, pI 5.7 Aplysia protein appears to be porin/voltage-dependent anion channel. Heat shock experiments on Aplysia eyes revealed that yet another one of the Aplysia proteins (70 kDa) affected by 5-HT appears to be a heat-inducible member (heat shock protein 70) of the family of heat shock proteins. These findings suggest that these three identified proteins, together or individually, may be involved in some way in the regulation of the timing of the circadian oscillator in the eye of Aplysia.
Koumenis
C
C
Department of Biochemical and Biophysical Sciences, University of Houston, Texas 77204, USA.
Nunez-Regueiro
M
M
Raju
U
U
Cook
R
R
Eskin
A
A
D000595:Amino Acid Sequence; D000818:Animals; D001048:Aplysia; D002352:Carrier Proteins / Q000235:genetics; D002940:Circadian Rhythm; D000242:Cyclic AMP / Q000031:analogs & derivatives / Q000494:pharmacology; D000091342:Endoplasmic Reticulum Chaperone BiP; D005123:Eye / Q000187:drug effects; D005136:Eye Proteins / Q000096:biosynthesis / Q000235:genetics*; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics; D006360:Heat-Shock Proteins; D006358:Hot Temperature; D006801:Humans; D018832:Molecular Chaperones / Q000235:genetics; D008969:Molecular Sequence Data; D009799:Ocular Physiological Phenomena; D017956:Photoreceptor Cells, Invertebrate / Q000187:drug effects* / Q000502:physiology; D018272:Porins / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D012701:Serotonin / Q000494:pharmacology*
D002352:Carrier Proteins; D000091342:Endoplasmic Reticulum Chaperone BiP; D005136:Eye Proteins; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; D018272:Porins; D012701:Serotonin; D000242:Cyclic AMP