Two domains of the progesterone receptor interact with the estrogen receptor and are required for progesterone activation of the c-Src/Erk pathway in mammalian cells.
In breast cancer cells, estrogens activate the Src/Erk pathway through an interaction of the estrogen receptor alpha (ERalpha) with the SH2 domain of c-Src. Progestins have been reported to activate also this pathway either via an interaction of the progesterone receptor isoform B (PRB) with ERalpha, which itself activates c-Src, or by direct interaction of PRB with the SH3 domain of c-Src. Here we identify two domains of PRB, ERID-I and -II, mediating a direct interaction with the ligand-binding domain of ERalpha. ERID-I and ERID-II flank a proline cluster responsible for binding of PRB to c-Src. In mammalian cells, the interaction of PRB with ERalpha and the progestin activation of the Src/Erk cascade are abolished by deletion of either ERID-I or ERID-II. These regions are not required for transactivation of a progesterone-responsive reporter gene. Mutations in the proline cluster of PRB that prevent a direct interaction with c-Src do not affect the strong activation of c-Src by progestins in the presence of ERalpha. Thus, in cells with ERalpha, ERID-I and ERID-II are necessary and sufficient for progestin activation of the endogenous Src/Erk pathway.
Ballaré
Cecilia
C
Institut für Molekularbiologie und Tumorforschung, Philipps-Universität, D-35033 Marburg, Germany.
Uhrig
Markus
M
Bechtold
Thomas
T
Sancho
Elena
E
Di Domenico
Marina
M
Migliaccio
Antimo
A
Auricchio
Ferdinando
F
Beato
Miguel
M
D000818:Animals; D001943:Breast Neoplasms / Q000473:pathology; D019556:COS Cells; D002522:Chlorocebus aethiops; D004789:Enzyme Activation / Q000187:drug effects; D047628:Estrogen Receptor alpha; D017930:Genes, Reporter; D006801:Humans; D020935:MAP Kinase Signaling System / Q000187:drug effects*; D019950:Mitogen-Activated Protein Kinase 1 / Q000502:physiology*; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000502:physiology*; D011374:Progesterone / Q000494:pharmacology*; D025941:Protein Interaction Mapping; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000378:metabolism; D011960:Receptors, Estrogen / Q000378:metabolism*; D011980:Receptors, Progesterone / Q000737:chemistry* / Q000187:drug effects / Q000378:metabolism; D013329:Structure-Activity Relationship; D015533:Transcriptional Activation; D014162:Transfection; D014407:Tumor Cells, Cultured; D020798:Two-Hybrid System Techniques; D018909:src Homology Domains
D047628:Estrogen Receptor alpha; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; C097314:progesterone receptor B; D011374:Progesterone; D016392:Proto-Oncogene Proteins pp60(c-src); D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases