Immunocytochemical localization of endopeptidase 24.15 in rat brain

Healy, Dennis P.; Orłowski, Marian

doi:10.1016/0006-8993(92)90517-d

Cited by 53 publications

(51 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Although TOP participation in the generation of Ang-(1-7) was first reported in vascular smooth muscle cells, 7 it had been described previously to act on other neuropeptides, 33 and some studies have found that this enzyme is widely distributed among different brain areas, such as cerebellum, hippocampus, cortex, and nucleus tractus solitarii. 34,35 In the current study, we show that Ang- (1-7) is the preferential peptide generated from AngI metabolism in hippocampal extracts from rats. Importantly, we describe that TOP plays a major enzymatic contribution to Ang-(1-7) formation, and that AngII formation is not observed.…”

Section: Downloaded Fromsupporting

confidence: 54%

Angiotensin II–Independent Angiotensin-(1–7) Formation in Rat Hippocampus

et al. 2013

View full text Add to dashboard Cite

The involvement and relevance of the renin–angiotensin system have been established clearly in cardiovascular diseases, and renin–angiotensin system involvement has also been investigated extensively in the central nervous system. Angiotensin II acts classically by binding to the AT 1 and AT 2 receptors. However, other pathways within the renin–angiotensin system have been described more recently, such as one in which angiotensin-(1–7) (Ang-(1–7)) binds to the receptor Mas. In the central nervous system specifically, it has been reported that this heptapeptide is involved in learning and memory processes that occur in central limbic regions, such as the hippocampus. Therefore, this prompted us to investigate the possible role of the Ang-(1–7)–receptor Mas pathway in epileptic seizures, which are also known to recruit limbic areas. In the present study, we show that Ang-(1–7) is the main metabolite of angiotensin I in rat hippocampi, and, strikingly, that thimet oligopeptidase is the main enzyme involved in the generation of Ang-(1–7). Furthermore, elevations in the levels of thimet oligopeptidase, Ang-(1–7), and of receptor Mas transcripts are observed in chronically stimulated epileptic rats, which suggest that the thimet oligopeptidase–Ang-(1–7)–receptor Mas axis may have a functional relevance in the pathophysiology of these animals. In summary, our data, which describe a new preferential biochemical pathway for the generation of Ang-(1–7) in the central nervous system and an increase in the levels of various elements of the related thimet oligopeptidase–Ang-(1–7)–receptor Mas pathway, unveil potential new roles of the renin–angiotensin system in central nervous system pathophysiology.

show abstract

Section: Downloaded Fromsupporting

confidence: 54%

Angiotensin II–Independent Angiotensin-(1–7) Formation in Rat Hippocampus

et al. 2013

View full text Add to dashboard Cite

show abstract

“…However, additional intracellular functions were suggested for EP24.15 (11,22) based on its predominant nuclear localization in the rat brain (66,14) and on the demonstration that EP24.15 participates in antigen presentation through the major histocompatibility class I (24,26,27). To investigate possible novel intracellular functions for this enzyme, we developed an experimental "substrate capture" assay that uses mutated, catalytically inactive EP24.15 and found its endogenous substrates to be fragments of intracellular proteins containing from 5 to 17 amino acids (22).…”

Section: Discussionmentioning

confidence: 99%

Intracellular Peptides as Natural Regulators of Cell Signaling

Cunha

Berti

Ferreira

et al. 2008

Journal of Biological Chemistry

138

View full text Add to dashboard Cite

Protein degradation by the ubiquitin proteasome system releases large amounts of oligopeptides within cells. To investigate possible functions for these intracellularly generated oligopeptides, we fused them to a cationic transactivator peptide sequence using reversible disulfide bonds, introduced them into cells, and analyzed their effect on G protein-coupled receptor (GPCR) signal transduction. A mixture containing four of these peptides (20 -80 M) significantly inhibited the increase in the extracellular acidification response triggered by angiotensin II (ang II) in CHO-S cells transfected with the ang II type 1 receptor (AT1R-CHO-S). Subsequently, either alone or in a mixture, these peptides increased luciferase gene transcription in AT1R CHO-S cells stimulated with ang II and in HEK293 cells treated with isoproterenol. These peptides without transactivator failed to affect GPCR cellular responses. All four functional peptides were shown in vitro to competitively inhibit the degradation of a synthetic substrate by thimet oligopeptidase. Overexpression of thimet oligopeptidase in both CHO-S and HEK293 cells was sufficient to reduce luciferase activation triggered by a specific GPCR agonist. Moreover, using individual peptides as baits in affinity columns, several proteins involved in GPCR signaling were identified, including ␣-adaptin A and dynamin 1. These results suggest that before their complete degradation, intracellular peptides similar to those generated by proteasomes can actively affect cell signaling, probably representing additional bioactive molecules within cells.

show abstract

“…The enzyme is broadly distributed, with high levels in neural and endocrine tissues such as brain, pituitary, ovary, and testis (Chu and Orlow ski, 1985). In the brain, the enzyme is widely expressed but is enriched in areas such as the hippocampus and neuroendocrine hypothalamus Healy and Orlowski, 1992;Wu et al, 1997).…”

Section: Introduction Ementioning

confidence: 99%

Secretion of Metalloendopeptidase 24.15 (EC 3.4.24.15)

Ferro

Tullai

Glucksman

et al. 1999

DNA and Cell Biology

View full text Add to dashboard Cite

The metalloendopeptidase EP24.15 (EC3.4.24.1 5) is a neuropeptide-metabolizing enzyme present in neural and endocrine tissues, presumably functioning extracellularly. Because the majority of the EP24.15 activity is identified in the soluble fraction of cellular homogenates, suggesting that the enzyme is primarily an intracellular protein, we addressed the issue of how EP24.15 arrives in the extracellular environment. We utilized a model system of neuroendocrine secretion, the AtT20 cell. According to both enzymatic activity and immunologic assays, EP24.15 was synthesized in and released from AtT20 cells. Under basal conditions and after stimulation by corticotropin-releasing hormone or the calcium ionophore A23187, EP24.15 activity accumulated in the culture medium. This secretion was not attributable to cell damage, as judged by the absence of release of cytosolic enzyme markers and the ability to exclude trypan blue dye. Pulse-chase analysis and subcellular fractionation of AtT20 cell extracts suggested that the mechanism of EP24.15 secretion is not solely via classical secretory pathways. Additionally, drugs which disrupt the classical secretory pathway, such as Brefeldin A and nocodazole, blocked A23187-stim ulated EP24.15 release yet had no effect on basal EP24.15 release, suggesting differences in the basal and stimulated pathways of secretion for EP24.15. In summary, EP24.15 appears to be secreted from AtT20 pituitary cells into the extracellular milieu, where the enzyme can participate in the physiologic metabolism of neuropeptides. 781

show abstract

Immunocytochemical localization of endopeptidase 24.15 in rat brain

Cited by 53 publications

References 19 publications

Angiotensin II–Independent Angiotensin-(1–7) Formation in Rat Hippocampus

Angiotensin II–Independent Angiotensin-(1–7) Formation in Rat Hippocampus

Intracellular Peptides as Natural Regulators of Cell Signaling

Secretion of Metalloendopeptidase 24.15 (EC 3.4.24.15)

Contact Info

Product

Resources

About