Protein-protein interactions that precede the nuclear entry of goat uterine estrogen receptor under cell-free conditions

Padma, A.; Renil, Manat; Thampan, Raghava Varman

doi:10.1002/1097-4644(20000915)78:4<650::aid-jcb14>3.0.co;2-w

Cited by 8 publications

(2 citation statements)

References 30 publications

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“…Several members of the Hsp family, including Hsp70, also have the capacity to bind to nuclear receptors, such as estrogen receptor alpha (Smith and Toft 1993). Hsps have been linked to the intracellular transport of steroid receptors (De Franco et al 1997;Sai Padma et al 2000) and can influence receptor-DNA interactions (Landel et al 1997). Recent work by Hurd et al (2000) found that transient transfection of Hsp70 produced a 2-to 3-fold increase in estrogen-stimulated estrogen response element-luciferase reporter activity in MCF-7 cells.…”

Section: Discussionmentioning

confidence: 99%

Expression of inducible Hsp70 enhances the proliferation of MCF-7 breast cancer cells and protects against the cytotoxic effects of hyperthermia

Barnes

Dix²,

Collins³

et al. 2001

Cell Stress Chaper

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Heat shock proteins (Hsps) are ubiquitous proteins that are induced following exposure to sublethal heat shock, are highly conserved during evolution, and protect cells from damage through their function as molecular chaperones. Some cancers demonstrate elevated levels of Hsp70, and their expression has been associated with cell proliferation, disease prognosis, and resistance to chemotherapy. In this study, we developed a tetracycline-regulated gene expression system to determine the specific effects of inducible Hsp70 on cell growth and protection against hyperthermia in MCF-7 breast cancer cells. MCF-7 cells expressing high levels of Hsp70 demonstrated a significantly faster doubling time (39 hours) compared with nonoverexpressing control cells (54 hours). The effect of elevated Hsp70 on cell proliferation was characterized further by 5-bromo-2'deoxyuridine labeling, which demonstrated a higher number of second and third division metaphases in cells at 42 and 69 hours, respectively. Estimates based on cell cycle analysis and mean doubling time indicated that Hsp70 may be exerting its growth-stimulating effect on MCF-7 cells primarily by shortening of the G0/G1 and S phases of the cell cycle. In addition to the effects on cell growth, we found that elevated levels of Hsp70 were sufficient to confer a significant level of protection against heat in MCF-7 cells. The results of this study support existing evidence linking Hsp70 expression with cell growth and cytoprotection in human cancer cells.

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Section: Discussionmentioning

confidence: 99%

Expression of inducible Hsp70 enhances the proliferation of MCF-7 breast cancer cells and protects against the cytotoxic effects of hyperthermia

Barnes

Dix²,

Collins³

et al. 2001

Cell Stress Chaper

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“…Studies carried out in our laboratory on the nuclear transport of goat uterine estrogen receptor α has clearly identified the involvement of two proteins: a 55 kDa protein (p55) that binds to the NLS on the ER and a 12 kDa protein (p12) that recognizes p55 on the one hand and a NPC protein on the other [Nirmala and Thampan, 1995; Sai Padma and Thampan, 2000; Sai Padma et al, 2000]. In the alternative estrogen receptor system that involves the naER, the NLS binding protein that mediates the transport of naER to the nucleus is a 58 kDa protein, p58.…”

mentioning

confidence: 99%

Proteins that mediate the nuclear entry of the goat uterine estrogen receptor activation factor (E‐RAF): Identification of a molecular basis for the inhibitory effect of progesterone on estrogen action

Govind

Sreekumar

Thampan

2003

J of Cellular Biochemistry

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A 66 kDa transport protein, tp66, has been identified as the protein that mediates the nuclear transport of the estrogen receptor activation factor (E-RAF). Indirect evidence shows that tp66 influences the transport of E-RAF mainly by recognizing the nuclear localization signals (NLS) on the latter. A 38 kDa nuclear pore complex protein (npcp38) has been identified to which tp66-E-RAF complex gets 'docked' prior to the nuclear entry of E-RAF. Progesterone binding to E-RAF serves to dissociate E-RAF from the tp66 thereby inhibiting the nuclear entry of E-RAF. The demonstration of the high affinity progesterone binding property of E-RAF adds credibility to the above findings. A change in conformation of E-RAF being brought about by progesterone binding is evident from the results of the circular dichroism (CD) analysis. This appears to be the fundamental reason behind the dissociation of the tp66-E-RAF complex under progesterone influence and provides a molecular basis for the estrogen 'antagonistic' action of progesterone. A nuclear run-on transcription assay clearly demonstrates the transcription-activation function of E-RAF II, also reaffirming the functional role of tp66 in the nuclear entry of E-RAF.

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TP73 alterations in cervical carcinoma

Craveiro

Costa

Pinto

et al. 2004

Cancer Genetics and Cytogenetics

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Protein-protein interactions that precede the nuclear entry of goat uterine estrogen receptor under cell-free conditions

Cited by 8 publications

References 30 publications

Expression of inducible Hsp70 enhances the proliferation of MCF-7 breast cancer cells and protects against the cytotoxic effects of hyperthermia

Expression of inducible Hsp70 enhances the proliferation of MCF-7 breast cancer cells and protects against the cytotoxic effects of hyperthermia

Proteins that mediate the nuclear entry of the goat uterine estrogen receptor activation factor (E‐RAF): Identification of a molecular basis for the inhibitory effect of progesterone on estrogen action

TP73 alterations in cervical carcinoma

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