title: Estradiol dependent anchoring of the goat uterine estrogen receptor activation factor (E-RAF) at the endoplasmic reticulum by a 55 kDa anchor protein (ap55).
abstract: The primary intracellular site of localization of the estrogen receptor activation factor (E-RAF) is shown here to be the endoplasmic reticulum where the protein remains anchored through an estrogen dependent mechanism. The retention of E-RAF by the endoplasmic reticulum is facilitated by two proteins: (1) a 55 kDa anchor protein (ap55) which is an integral membrane protein of the endoplasmic reticulum. ap55 is a high affinity estrogen binding protein. A conformational change induced by estrogen binding is thought to favor the anchoring process. (2) The anchoring of E-RAF by ap55 is mediated by yet another protein. This is the 66 kDa transport protein (tp66) which recognizes ap55 on the one hand and E-RAF on the other. The presence of estradiol that saturates the hormone binding sites on ap55 appears to favor the anchoring of tp66-E-RAF complex to ap55. This interaction appears to be weakened by levels of estradiol below 7 nM concentration leading to the dissociation of the tp66-E-RAF complex from ap55. The tp66-E-RAF complex moves towards the nucleus.
authors.affiliation: Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram-695014, Kerala, India.
authors.forename: Anitha P
authors.initials: AP
authors.lastname: Govind
authors.forename: S
authors.initials: S
authors.lastname: Sreeja
authors.forename: Raghava Varman
authors.initials: RV
authors.lastname: Thampan
mesh_terms: D021581:Active Transport, Cell Nucleus; D000818:Animals; D001665:Binding Sites; D002352:Carrier Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D004958:Estradiol / Q000378:metabolism*; D005260:Female; D006023:Glycoproteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D006041:Goats; D066298:In Vitro Techniques; D008565:Membrane Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D008970:Molecular Weight; D011506:Proteins / Q000378:metabolism*; D011960:Receptors, Estrogen; D014599:Uterus / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D006023:Glycoproteins; D008565:Membrane Proteins; D011506:Proteins; D011960:Receptors, Estrogen; C010140:estrophilin; D004958:Estradiol