Cellular variations in heterotrimeric G protein localization and expression in rat pituitary
- PMID: 8275939
- DOI: 10.1210/endo.134.1.8275939
Cellular variations in heterotrimeric G protein localization and expression in rat pituitary
Abstract
The secretory cells of the anterior pituitary are regulated by hypothalamic and target endocrine hormones. In many cases, intracellular signaling after ligand binding to cell surface receptors is mediated by heterotrimeric G proteins. In this study, cells from the rat pituitary and two pituitary cell lines (GH3 and AtT-20 cells) were doubly labeled by immunofluorescence with specific rabbit antibodies to the alpha-subunits of G proteins (Gs, Gi1-3, or Gq) and monoclonal antibodies against pituitary hormones (GH, PRL, beta LH, beta TSH, or beta FSH) to identify specific cell types. Gs, Gi, and Gq were detected in all secretory types, but differences were found in their levels of expression and cellular distribution. The cell periphery was the predominant site of localization of all these G proteins. In addition, both Gi3 and at least one member of the Gq family were seen by immunofluorescence on intracellular sites typical of the Golgi region. By immunogold labeling, alpha i3 was localized to membranes of Golgi cisternae in sections of rat pituitary and GH3 cells, where it was concentrated on the cis-side of the Golgi stack. These findings demonstrate that G proteins are widely expressed in anterior pituitary cells and further support a role for Gi alpha 3, and possibly Gs, in intracellular membrane trafficking.
Similar articles
-
Differential distribution of alpha subunits and beta gamma subunits of heterotrimeric G proteins on Golgi membranes of the exocrine pancreas.J Cell Biol. 1996 Jun;133(5):1027-40. doi: 10.1083/jcb.133.5.1027. J Cell Biol. 1996. PMID: 8655576 Free PMC article.
-
Identification of multiple subunits of heterotrimeric G proteins on the membrane of secretory granules in rat prolactin anterior pituitary cells.Mol Cell Neurosci. 1994 Dec;5(6):556-66. doi: 10.1006/mcne.1994.1068. Mol Cell Neurosci. 1994. PMID: 7704429
-
Distribution and role of heterotrimeric G proteins in the secretory pathway of polarized epithelial cells.J Cell Sci Suppl. 1993;17:33-9. doi: 10.1242/jcs.1993.supplement_17.6. J Cell Sci Suppl. 1993. PMID: 8144703 Review.
-
Lipocortin 1 (annexin 1): a candidate paracrine agent localized in pituitary folliculo-stellate cells.Endocrinology. 1999 Sep;140(9):4311-9. doi: 10.1210/endo.140.9.7008. Endocrinology. 1999. PMID: 10465305
-
Identification of G proteins in lacrimal gland.Invest Ophthalmol Vis Sci. 1995 May;36(6):1173-80. Invest Ophthalmol Vis Sci. 1995. PMID: 7730026
Cited by
-
Subtype-dependent regulation of Gβγ signalling.Cell Signal. 2021 Jun;82:109947. doi: 10.1016/j.cellsig.2021.109947. Epub 2021 Feb 11. Cell Signal. 2021. PMID: 33582184 Free PMC article. Review.
-
Close association of the alpha subunits of Gq and G11 G proteins with actin filaments in WRK1 cells: relation to G protein-mediated phospholipase C activation.Proc Natl Acad Sci U S A. 1995 Aug 29;92(18):8413-17. doi: 10.1073/pnas.92.18.8413. Proc Natl Acad Sci U S A. 1995. PMID: 7667304 Free PMC article.
-
Galpha i3 binding to calnuc on Golgi membranes in living cells monitored by fluorescence resonance energy transfer of green fluorescent protein fusion proteins.Proc Natl Acad Sci U S A. 2001 Dec 18;98(26):14961-6. doi: 10.1073/pnas.261572098. Proc Natl Acad Sci U S A. 2001. PMID: 11752444 Free PMC article.
-
Dopamine D2 receptor stimulation alters G-protein expression in rat pituitary intermediate lobe melanotropes.Endocrine. 1997 Jun;6(3):325-33. doi: 10.1007/BF02820510. Endocrine. 1997. PMID: 9368690
-
Wortmannin-sensitive phosphorylation, translocation, and activation of PLCgamma1, but not PLCgamma2, in antigen-stimulated RBL-2H3 mast cells.Mol Biol Cell. 1998 Feb;9(2):483-96. doi: 10.1091/mbc.9.2.483. Mol Biol Cell. 1998. PMID: 9450969 Free PMC article.
Publication types
MeSH terms
Substances
Grants and funding
LinkOut - more resources
Full Text Sources
