2301
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Abstract
Autoreactive lymphocytes are suppressed in healthy individuals by so-called peripheral tolerance. Accumulating evidence indicates that co-receptor signaling plays a pivotal role in the regulation of autoreactive lymphocytes. The positive regulatory co-receptors CD28 and inducible co-stimulator (ICOS) transduce stimulatory cosignals, whereas the negative regulatory co-stimulators CTLA-4 and PD-1 are critical for the regulation of peripheral tolerance and autoimmunity. PD-1 deficient mice develop lupus-like glomerulonephritis and arthritis on a C57Bl/6 background and autoimmune-dilated cardiomyopathy on a BALB/c background.
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Affiliation(s)
- Taku Okazaki
- Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Yoshida-Konoe, Sakyo-ku, Kyoto, Japan
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2302
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Maishi N, Annan DA, Kikuchi H, Hida Y, Hida K. An antiestrogen-binding protein in human tissues. Cancers (Basel) 1983; 11:cancers11101511. [PMID: 31600937 PMCID: PMC6826555 DOI: 10.3390/cancers11101511] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Revised: 10/01/2019] [Accepted: 10/02/2019] [Indexed: 12/22/2022] Open
Abstract
Although nonsteroidal antiestrogens of the triphenylethylene type are generally considered to act through the estrogen receptor, some observations suggest that estrogen target tissues may also contain a binding protein specific for these compounds. The data so far reported, however, are also consistent with ligand-induced changes in conformation or in the state of aggregation of the estrogen receptor. The studies reported here demonstrate the existence of a protein in human myometrial cytosol which binds 1-[4-(2-dimethylaminoethoxy)phenyl]1,2-diphenylbut-1(Z)-ene ([3H]tamoxifen) with high affinity (Kd = 2.3 X 10(-9) M). This protein exhibits striking specificity for nonsteroidal antiestrogens. Estradiol competes weakly for bound [3H]tamoxifen, while other estrogens and nonestrogenic steroid hormones do not compete at all. Sedimentation analysis and molecular sieve chromatography indicate that the antiestrogen-binding protein is a larger species than the estrogen receptor and elutes from DEAE-Sephacel at a lower KCl concentration (0.03 M) than the estrogen receptor (0.15 M). Differential thermal stability of the estrogen receptor and the antiestrogen-binding protein was demonstrable in the absence of added ligand. The antiestrogen-binding protein was ubiquitous, being present in many tissues where estrogen receptor was undetectable. These findings support the separate existence of an antiestrogen-binding protein.
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Affiliation(s)
- Nako Maishi
- Department of Vascular Biology and Molecular Pathology, Hokkaido University Graduate School of Dental Medicine, Sapporo 060-8586, Japan.
- Vascular Biology, Frontier Research Unit, Institute for Genetic Medicine, Hokkaido University, Sapporo 060-0815, Japan.
| | - Dorcas A Annan
- Department of Vascular Biology and Molecular Pathology, Hokkaido University Graduate School of Dental Medicine, Sapporo 060-8586, Japan.
- Vascular Biology, Frontier Research Unit, Institute for Genetic Medicine, Hokkaido University, Sapporo 060-0815, Japan.
| | - Hiroshi Kikuchi
- Vascular Biology, Frontier Research Unit, Institute for Genetic Medicine, Hokkaido University, Sapporo 060-0815, Japan.
- Department of Renal and Genitourinary Surgery, Hokkaido University Graduate School of Medicine, Sapporo 060-8636, Japan.
| | - Yasuhiro Hida
- Department of Cardiovascular and Thoracic Surgery, Hokkaido University Faculty of Medicine, Sapporo 060-8638, Japan.
| | - Kyoko Hida
- Department of Vascular Biology and Molecular Pathology, Hokkaido University Graduate School of Dental Medicine, Sapporo 060-8586, Japan.
- Vascular Biology, Frontier Research Unit, Institute for Genetic Medicine, Hokkaido University, Sapporo 060-0815, Japan.
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