Colocalization of pinopsin with two types of G-protein α-subunits in the chicken pineal gland

A. Matsushita, T. Yoshikawa, T. Okano, T. Kasahara, Y. Fukada

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)


Pinopsin is a photoreceptive molecule present in the outer segments of chicken pinealocytes. In this paper, the localization of α-subunits of G-proteins, rod transducin (Gt1) and Gq/11, was examined by immunoelectron microscopy to investigate whether these G-proteins colocalize with pinopsin in the outer segments. Ultrathin sections of the chicken pineal gland were double-immunolabeled with antibodies to pinopsin and either Gt1α or Gq/11α. As shown previously, the outer segments around the follicular lumen exhibited divergent morphology with ciliary, bulbous, or lamellate shapes, and most of them displayed pinopsin immunoreactivity. The majority (> 90%) of pinopsin-immunopositive outer segments were labeled by anti-Gt1α and/or anti-Gq/11α antibodies. Application of double-immunolabeling to serial sections demonstrated that a large number of the pinopsin-immunopositive outer segments contained both Gt1α and Gq/11α immunoreactivities. These results suggest that Gt1α and Gq/11α are functionally coupled with light-activated pinopsin within a single outer segment.

Original languageEnglish
Pages (from-to)245-251
Number of pages7
JournalCell and Tissue Research
Issue number2
Publication statusPublished - 2000
Externally publishedYes


  • Chicken
  • Circadian clock
  • Gq/11
  • Immunoelectron microscopy
  • Phototransduction
  • Pinealocyte
  • Rod transducin

ASJC Scopus subject areas

  • Pathology and Forensic Medicine
  • Histology
  • Cell Biology


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