Biomedical subjects

Julia Fernandez-Rodriguez

Publications and source records attributed to Julia Fernandez-Rodriguez.

7 recordsLinked to original sources

PubMed2006

Quantitative proteomics analysis of the secretory pathway.

We report more than 1400 proteins of the secretory-pathway proteome and provide spatial information on the relative presence of each protein in the rough and smooth ER Golgi cisternae and Golgi-derived COPI vesicles. The data support a role for COPI vesicles in recycling and cisternal maturation, showing that Golgi-resident proteins are present at a higher concentration than secretory cargo. Of the 1400 proteins, 345 were identified as previously uncharacterized. Of these, 230 had their subcellular location deduced by proteomics. This study provides a comprehensive catalog of the ER and Golgi proteomes with insight into their identity and function.

Animals↗

PubMed2006

Estrogen-induced upregulation of AR expression and enhancement of AR nuclear translocation in mouse fallopian tubes in vivo.

Female mice lacking AR display alterations in ovarian and uterine function. However, the biology of AR in the fallopian tube is not fully understood. To gain an insight into potential roles of AR in this tissue, we demonstrated that eCG treatment increased AR expression in a time-dependent manner and subsequent treatment with hCG decreased AR expression in mouse fallopian tubes. This expression pattern was positively associated with 17beta-estradiol and testosterone levels in vivo. Immunohistochemical analysis of fallopian tube epithelial cells revealed that nuclear localization of AR increased in parallel with decreased AR in the cytoplasm following eCG treatment. Moreover, we found that treatment with flutamide upregulated AR expression in immature mice in association with a decrease in serum testosterone levels, whereas the same treatment resulted in downregulation of AR expression in gonadotropin-stimulated mice with concomitant decreases in serum 17beta-estradiol concentrations, suggesting that androgen differs from estrogen in the regulation of AR expression. Furthermore, we demonstrated that DES increased both AR protein expression and nuclear location over a 48-h time course. DHT had rapid effects, with induction of AR expression and translocation at 6 h after injection, but unlike DES it had prolonged efficacy. In addition, we provided direct in vivo evidence that nuclear protein interaction between AR and p21(Cip1), a previously reported AR-regulated gene, was enhanced by gonadotropin stimulation. To our knowledge, this study provides the first demonstration to illustrate that estrogen as a principal regulator may contribute to regulate and activate AR in the fallopian tubes in vivo.

Animals↗

PubMed2006

Nuclear progesterone receptor A and B isoforms in mouse fallopian tube and uterus: implications for expression, regulation, and cellular function.

Progesterone and its interaction with nuclear progesterone receptors (PR) PR-A and PR-B play a critical role in the regulation of female reproductive function in all mammals. However, our knowledge of the regulation and possible cellular function of PR protein isoforms in the fallopian tube and uterus in vivo is still very limited. In the present study, we revealed that equine chorionic gonadotropin (eCG) treatment resulted in a time-dependent increase in expression of both isoforms, reaching a maximal level at 48 h in the fallopian tube. Regulation of PR-A protein expression paralleled that of PR-B protein expression. However, in the uterus PR-B protein levels increased and peaked earlier than PR-A protein levels after eCG treatment. With prolonged exposure to eCG, PR-B protein levels decreased, whereas PR-A protein levels continued to increase. Furthermore, subsequent treatment with human (h)CG decreased the levels of PR protein isoforms in both tissues in parallel with increased endogenous serum progesterone levels. To further elucidate whether progesterone regulates PR protein isoforms, we demonstrated that a time-dependent treatment with progesterone (P(4)) decreased the expression of PR protein isoforms in both tissues, whereas decreases in p27, cyclin D(2), and proliferating cell nuclear antigen protein levels were observed only in the uterus. To define the potential PR-mediated effects on apoptosis, we demonstrated that the PR antagonist treatment increased the levels of PR protein isoforms, induced mitochondrial-associated apoptosis, and decreased in epidermal growth factor (EGF) and EGF receptor protein expression in both tissues. Interestingly, immunohistochemistry indicated that the induction of apoptosis by PR antagonists was predominant in the epithelium, whereas increase in PR protein expression was observed in stromal cells of both tissues. Taken together, these observations suggest that 1) the tissue-specific and hormonal regulation of PR isoform expression in mouse fallopian tube and uterus, where they are potentially involved in regulation of mitochondrial-mediated apoptosis depending on the cellular compartment; and 2) a possible interaction between functional PR protein and growth factor signaling may have a coordinated role for regulating apoptotic process in both tissues in vivo.

Animals↗

PubMed2006

Developmental and hormonal regulation of progesterone receptor A-form expression in female mouse lung in vivo: interaction with glucocorticoid receptors.

Progesterone (P(4)) regulates many aspects of physiological functions via two nuclear P(4) receptors (PR), PRA and PRB, which are members of a structurally related nuclear hormone receptor superfamily that includes glucocorticoid receptors (GR). The regulation and cellular distribution of PR protein isoforms have been extensively studied in reproductive tissues, but this is not the case in the lung. In the present study, reverse transcriptase (RT)-PCR, Western blotting, and immunolocalization supported the presence of PRA in the lung of female mice, with PRA protein levels significantly increased between postnatal day 7 and 12, declined at postnatal day 26, and minimal in adults when compared to postnatal day 2. The peak was temporally related to postnatal lung maturation in rodents. Immunoreactivity for PR was detected in the alveolar and bronchial epithelia. We then extended this study to examine, for the first time, the regulation of PRA protein expression in female mouse lung in vivo. Neither the increase in endogenous P(4) nor treatment with exogenous P(4) regulated PRA protein expression in female mouse lung. However, treatment of mice with the GR/PR antagonist RU 486, but not Org 31710 (a specific PR antagonist), significantly increased PRA protein expression in parallel to a decrease in GR protein expression. In addition, treatment with the synthetic glucocorticoid dexamethasone led to a decrease in PRA protein expression independent of endogenous P(4) levels. Furthermore, immunoprecipitation followed by Western blot analysis revealed that, under in vivo conditions, PRA physically interacted with GR in mouse lung. Confocal laser microscopy revealed that PRA and GR co-localized in the nuclei of alveolar epithelia cells, whereas nuclear PR and cytoplasmic GR were detected in bronchial epithelium. Taken together, our observations suggest that PRA may be an important physiological factor involved in postnatal lung development and that the regulation of PRA protein expression is not dependent on P(4), but rather on functional glucocorticoid/GR signaling mediated by protein-protein interaction in the mouse lung.

Animals↗

PubMed2005

Shedding and gamma-secretase-mediated intramembrane proteolysis of the mucin-type molecule CD43.

CD43 is a transmembrane molecule that contains a 123-aminoacids-long cytoplasmic tail and a highly O-glycosylated extracellular domain of mucin type. Endogenous CD43 expressed in COLO 205, K562 and Jurkat cells revealed a membrane-associated, 20 kDa CD43-specific cytoplasmic tail fragment (CD43-CTF) upon inhibition of gamma-secretase. This fragment was formed by an extracellular cleavage, as it was not accumulated after treating cells with 1,10-phenanthroline, a metalloprotease inhibitor. When CD43 was transfected into HEK-293 cells expressing dominant-negative PS1 (presenilin-1), the CD43-CTF was accumulated, but not in cells with wild-type PS1. Owing to its accumulation in the presence of a non-functional PS variant, it may thus be a novel gamma-secretase substrate. This CTF is formed by an extracellular cleavage close to the membrane, is a fragment that can be concluded to be a substrate for gamma-secretase. However, the intracellular gamma-secretase product has not been possible to detect, suggesting a quick processing of this product. During normal growth the CTF was not found without gamma-secretase inhibition, but when the cells (COLO 205) were very confluent the fragment could be detected. The intracellular domain of CD43 has previously been shown to contain a functional nuclear localization signal, and has been suggested to be involved in gene activation. From this and the present results, a novel way to explain how mucin-type molecules may transduce intracellular signals can be proposed.

Amyloid Precursor Protein Secretases↗

PubMed2004

MUC1 can interact with adenomatous polyposis coli in breast cancer.

The MUC1 tumor antigen is overexpressed on most breast tumors and metastases. It interacts with signaling proteins such as the ErbB kinases and beta-catenin, and is involved in mammary gland oncogenesis and tumor progression. Herein, we report a novel interaction between MUC1 and adenomatous polyposis coli (APC), a tumor suppressor involved in downregulating beta-catenin signaling. Initially identified in colorectal cancer, APC is also downregulated in breast tumors and presumably involved in mammary carcinogenesis. MUC1 and APC co-immunoprecipitate from the ZR-75-1 human breast carcinoma cell line and co-localize in mouse mammary glands and tumors. These studies also indicate that the association of MUC1 and APC may be increased by epidermal growth factor stimulation. Intriguingly, the co-immunoprecipitation of MUC1 and APC increases in human breast tumors and metastases as compared to adjacent normal tissues, indicating that this association may play a role in the formation and progression of breast tumors.

Adenomatous Polyposis Coli Protein↗

PubMed2004

CD43 has a functional NLS, interacts with beta-catenin, and affects gene expression.

CD43 is a transmembrane molecule with a highly O-glycosylated extracellular domain of mucin type. It is a normal constituent of leukocytes and found in colon adenoma, but not in normal colon epithelia. Here it is shown that the cytoplasmic tail of CD43 contains a functional bipartite nuclear localization signal directing it to the nucleus. The intracellular domain of CD43 interacts with beta-catenin and causes an upregulation of the beta-catenin target genes c-MYC and CyclinD1. The present results suggest that CD43 can be involved in nuclear signaling and via beta-catenin interaction be involved in cell proliferation.

Amino Acid Sequence↗