Multiple growth hormone-binding proteins are expressed on insulin-producing cells
Møldrup, Annette ; Billestrup, Nils ; Thorn, Niels A. ; Lernmark, Åke LU
and Nielsen, Jens Høiriis
(1989)
In Molecular Endocrinology
3(8).
p.1173-1182
- Abstract
The insulin-producing rat islet tumor cell line, RIN-5AH, expresses somatogen binding sites and responds to GH by increased proliferation and insulin production. Affinity cross-linking shows that RIN-5AH cells contain two major GH-binding subunits of Mr 100-130K (110K), which appear to exist as disulfide-linked multimers of Mr 270-350K (300K). In addition, a minor Mr 180K GH-binding protein is identified which does not appear to be associated with other proteins by disulfide bridges. A plasma membrane-enriched fraction accounts for 86% of the RIN-cell GH-binding activity while cytosol and intracellular organelles are low in GH-binding activity. The plasma membrane-bound activity is soluble in Triton X-100 with intact hormone binding... (More)
The insulin-producing rat islet tumor cell line, RIN-5AH, expresses somatogen binding sites and responds to GH by increased proliferation and insulin production. Affinity cross-linking shows that RIN-5AH cells contain two major GH-binding subunits of Mr 100-130K (110K), which appear to exist as disulfide-linked multimers of Mr 270-350K (300K). In addition, a minor Mr 180K GH-binding protein is identified which does not appear to be associated with other proteins by disulfide bridges. A plasma membrane-enriched fraction accounts for 86% of the RIN-cell GH-binding activity while cytosol and intracellular organelles are low in GH-binding activity. The plasma membrane-bound activity is soluble in Triton X-100 with intact hormone binding characteristics. The apparent KD in detergent solution is estimated to 18 ng/ml (8 x 10-10 m).125l-hGH-affinity cross-linking to intact and detergent-solubilized membranes as well as hGH-affinity purified protein reveals labeled proteins of Mr 180K and Mr 285-350K. In contrast to the cross-linked Mr 300K complexes of intact cells those of disintegrated cellular material are resistant to reduction with dithiothreitol, and it is speculated that this is due to intersubunit cross-linking of the disulfide-linked Mr 110K GH-binding subunits. The GH-binding proteins are purified approximately 100-fold by one cycle of hGH-affinity chromatography and five major proteins of Mr 180K, 94K, 86K, 64K, and 54K are identified by silver staining in the purified fraction. It is concluded that the RIN-5AH cells have multiple GH-binding proteins which may mediate signals for either proliferation and/or insulin production.
(Less)
- author
- Møldrup, Annette
; Billestrup, Nils
; Thorn, Niels A.
; Lernmark, Åke
LU
and Nielsen, Jens Høiriis
- publishing date
- 1989-01-01
- type
- Contribution to journal
- publication status
- published
- in
- Molecular Endocrinology
- volume
- 3
- issue
- 8
- pages
- 10 pages
- publisher
- The Endocrine Society
- external identifiers
-
- scopus:0024339019
- pmid:2674691
- ISSN
- 0888-8809
- DOI
- 10.1210/mend-3-8-1173
- language
- English
- LU publication?
- no
- id
- e8b23895-d0c2-4619-8f08-77ed707ba879
- date added to LUP
- 2019-09-11 10:00:56
- date last changed
- 2024-03-13 08:12:22
@article{e8b23895-d0c2-4619-8f08-77ed707ba879,
abstract = {{<p>The insulin-producing rat islet tumor cell line, RIN-5AH, expresses somatogen binding sites and responds to GH by increased proliferation and insulin production. Affinity cross-linking shows that RIN-5AH cells contain two major GH-binding subunits of Mr 100-130K (110K), which appear to exist as disulfide-linked multimers of Mr 270-350K (300K). In addition, a minor Mr 180K GH-binding protein is identified which does not appear to be associated with other proteins by disulfide bridges. A plasma membrane-enriched fraction accounts for 86% of the RIN-cell GH-binding activity while cytosol and intracellular organelles are low in GH-binding activity. The plasma membrane-bound activity is soluble in Triton X-100 with intact hormone binding characteristics. The apparent K<sub>D</sub> in detergent solution is estimated to 18 ng/ml (8 x 10<sup>-10</sup> m).<sup>125</sup>l-hGH-affinity cross-linking to intact and detergent-solubilized membranes as well as hGH-affinity purified protein reveals labeled proteins of Mr 180K and Mr 285-350K. In contrast to the cross-linked Mr 300K complexes of intact cells those of disintegrated cellular material are resistant to reduction with dithiothreitol, and it is speculated that this is due to intersubunit cross-linking of the disulfide-linked Mr 110K GH-binding subunits. The GH-binding proteins are purified approximately 100-fold by one cycle of hGH-affinity chromatography and five major proteins of Mr 180K, 94K, 86K, 64K, and 54K are identified by silver staining in the purified fraction. It is concluded that the RIN-5AH cells have multiple GH-binding proteins which may mediate signals for either proliferation and/or insulin production.</p>}},
author = {{Møldrup, Annette and Billestrup, Nils and Thorn, Niels A. and Lernmark, Åke and Nielsen, Jens Høiriis}},
issn = {{0888-8809}},
language = {{eng}},
month = {{01}},
number = {{8}},
pages = {{1173--1182}},
publisher = {{The Endocrine Society}},
series = {{Molecular Endocrinology}},
title = {{Multiple growth hormone-binding proteins are expressed on insulin-producing cells}},
url = {{http://dx.doi.org/10.1210/mend-3-8-1173}},
doi = {{10.1210/mend-3-8-1173}},
volume = {{3}},
year = {{1989}},
}