Rod-type transducin α-subunit mediates a phototransduction pathway in the chicken pineal gland

Takaoki Kasahara, Toshiyuki Okano, Tomoko Yoshikawa, Kazumitsu Yamazaki, Yoshitaka Fukada

Research output: Contribution to journalArticle

32 Citations (Scopus)

Abstract

The chicken pineal gland is a photosensitive neuroendocrine organ producing melatonin in circadian clock-regulated and light-sensitive manners. To understand the relationship between the photoreceptive molecule pinopsin and the light-dependent melatonin suppression that is sensitive to pertussis toxin treatment, we have searched for pertussis toxin-sensitive G protein α- subunits expressed in the chicken pineal gland. Here we report the cDNA cloning of the pineal transducin α-subunit (Gtα), which is highly homologous to human retinal rod cell-specific Gt1α. Concurrent cDNA cloning of chicken retinal Gt1α and Gt2α (rod and cone cell-specific α-subunits of transducin, respectively) revealed that the chicken pineal Gtα is identical to the retinal Gt1α. Double-immunostaining analysis of the chicken pineal sections localized Gt1α-immunoreactivity in the rudimentary outer segments of both follicular and parafollicular pinealocytes that were immunopositive to anti-pinopsin antibody. To examine whether pineal Gt1α is involved in the pineal phototransduction pathway, trypsin protection assay was applied for detecting the conversion of GDP-bound Gt1α into the guanosine 5'-O-(3-thiotriphosphate) (GTPγS)-bound form in the pineal membrane homogenate. It was clearly demonstrated that the pineal Gt1α is activated in a light-dependent manner in the presence of GTPγS. These data together suggest strongly that pineal Gt1α mediates the phototransduction pathway triggered by pinopsin in the chicken pinealocytes.

Original languageEnglish
Pages (from-to)217-224
Number of pages8
JournalJournal of Neurochemistry
Volume75
Issue number1
DOIs
Publication statusPublished - 2000
Externally publishedYes

Fingerprint

Transducin
Light Signal Transduction
Pineal Gland
Chickens
Cloning
Pertussis Toxin
Melatonin
Complementary DNA
Guanosine 5'-O-(3-Thiotriphosphate)
Protein Subunits
GTP-Binding Proteins
Light
Trypsin
Cones
Organism Cloning
Clocks
Assays
Membranes
Retinal Rod Photoreceptor Cells
Vertebrate Photoreceptor Cells

Keywords

  • G protein
  • Phototransduction
  • Pineal gland
  • Pinopsin
  • Transducin
  • Trypsin protection assay

ASJC Scopus subject areas

  • Biochemistry
  • Cellular and Molecular Neuroscience

Cite this

Rod-type transducin α-subunit mediates a phototransduction pathway in the chicken pineal gland. / Kasahara, Takaoki; Okano, Toshiyuki; Yoshikawa, Tomoko; Yamazaki, Kazumitsu; Fukada, Yoshitaka.

In: Journal of Neurochemistry, Vol. 75, No. 1, 2000, p. 217-224.

Research output: Contribution to journalArticle

Kasahara, Takaoki ; Okano, Toshiyuki ; Yoshikawa, Tomoko ; Yamazaki, Kazumitsu ; Fukada, Yoshitaka. / Rod-type transducin α-subunit mediates a phototransduction pathway in the chicken pineal gland. In: Journal of Neurochemistry. 2000 ; Vol. 75, No. 1. pp. 217-224.
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