Protein kinase C-mediated phosphorylation of retinal rod outer segment membrane proteins

Ronit Sagi-Eisenberg, Linton M. Traub, Allen M. Spiegel, Yehiel Zick

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

In the present study we demonstrate that TD-α undergoes phosphorylation by PKC when present in its native form in intact ROS membranes. This phosphorylation is inhibited by GTP-γ-S which activates TD, suggesting that it is only the inactive conformation of TD-α that serves as a substrate for PKC. Indeed, both vanadate and AlF4, that confer an active conformation on TD-α-GDP, inhibit PKC-mediated phosphorylation of purified TD-α-GDP. We demonstrate that the purified β subunit of TD also serves as an in vitro substrate for PKC. Moreover, following their phosphorylation, both TD-α and β from high affinity complexes with PKC. This is evident from the findings that PKC coprecipitates with both the α and β subunits of TD when the latter are immunoprecipitated by their respective antibodies. PKC phosphorylates additional ROS proteins of 36, 48 and 92 kDa, tentatively identified as rhodopsin, arrestin and the cGMP-phosphodiesterase. Taken together our results strongly suggest that phosphorylation of TD is of physiological relevance and that through phosphorylation of endogenous ROS proteins, PKC could play a key role in regulating phototransduction.

Original languageEnglish (US)
Pages (from-to)519-531
Number of pages13
JournalCellular Signalling
Volume1
Issue number5
DOIs
StatePublished - 1989
Externally publishedYes

Fingerprint

Retinal Photoreceptor Cell Outer Segment
Rod Cell Outer Segment
Retinal Rod Photoreceptor Cells
Protein Kinase C
Membrane Proteins
Phosphorylation
Light Signal Transduction
Arrestin
Rhodopsin
Vanadates
Phosphoric Diester Hydrolases
Guanosine Triphosphate
Proteins
Membranes
Antibodies

Keywords

  • G-protein
  • phosphorylation
  • Protein kinase C
  • rod outer segment
  • transducin

ASJC Scopus subject areas

  • Cell Biology

Cite this

Protein kinase C-mediated phosphorylation of retinal rod outer segment membrane proteins. / Sagi-Eisenberg, Ronit; Traub, Linton M.; Spiegel, Allen M.; Zick, Yehiel.

In: Cellular Signalling, Vol. 1, No. 5, 1989, p. 519-531.

Research output: Contribution to journalArticle

Sagi-Eisenberg, Ronit ; Traub, Linton M. ; Spiegel, Allen M. ; Zick, Yehiel. / Protein kinase C-mediated phosphorylation of retinal rod outer segment membrane proteins. In: Cellular Signalling. 1989 ; Vol. 1, No. 5. pp. 519-531.
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N2 - In the present study we demonstrate that TD-α undergoes phosphorylation by PKC when present in its native form in intact ROS membranes. This phosphorylation is inhibited by GTP-γ-S which activates TD, suggesting that it is only the inactive conformation of TD-α that serves as a substrate for PKC. Indeed, both vanadate and AlF4, that confer an active conformation on TD-α-GDP, inhibit PKC-mediated phosphorylation of purified TD-α-GDP. We demonstrate that the purified β subunit of TD also serves as an in vitro substrate for PKC. Moreover, following their phosphorylation, both TD-α and β from high affinity complexes with PKC. This is evident from the findings that PKC coprecipitates with both the α and β subunits of TD when the latter are immunoprecipitated by their respective antibodies. PKC phosphorylates additional ROS proteins of 36, 48 and 92 kDa, tentatively identified as rhodopsin, arrestin and the cGMP-phosphodiesterase. Taken together our results strongly suggest that phosphorylation of TD is of physiological relevance and that through phosphorylation of endogenous ROS proteins, PKC could play a key role in regulating phototransduction.

AB - In the present study we demonstrate that TD-α undergoes phosphorylation by PKC when present in its native form in intact ROS membranes. This phosphorylation is inhibited by GTP-γ-S which activates TD, suggesting that it is only the inactive conformation of TD-α that serves as a substrate for PKC. Indeed, both vanadate and AlF4, that confer an active conformation on TD-α-GDP, inhibit PKC-mediated phosphorylation of purified TD-α-GDP. We demonstrate that the purified β subunit of TD also serves as an in vitro substrate for PKC. Moreover, following their phosphorylation, both TD-α and β from high affinity complexes with PKC. This is evident from the findings that PKC coprecipitates with both the α and β subunits of TD when the latter are immunoprecipitated by their respective antibodies. PKC phosphorylates additional ROS proteins of 36, 48 and 92 kDa, tentatively identified as rhodopsin, arrestin and the cGMP-phosphodiesterase. Taken together our results strongly suggest that phosphorylation of TD is of physiological relevance and that through phosphorylation of endogenous ROS proteins, PKC could play a key role in regulating phototransduction.

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