Cathepsin D is the primary protease for the generation of adenohypophyseal vasoinhibins: Cleavage occurs within the prolactin secretory granules
Por:
Cruz-Soto M.E., Cosío G., Jeziorski M.C., Vargas-Barroso V., Aguilar M.B., Cárabez A., Berger P., Saftig P., Arnold E., Thebault S., De La Escalera G.M., Clapp C.
Publicada:
1 dic 2009
Categoría:
Endocrinology
Resumen:
Vasoinhibins are a family of N-terminal prolactin (PRL) fragments that inhibit blood vessel growth, dilation, permeability, and survival. The aspartyl endoprotease cathepsin D is active at acidic pH and can cleave rat PRL to generate vasoinhibins. We investigated whether and where vasoinhibins could be generated by cathepsin D in the adenohypophysis of rats and mice and whether their production could be gender dependent. Vasoinhibins were detected in primary cultures of rat adenohypophyseal cells by Western blot with antibodies directed against the N terminus of PRL but not the C terminus. Ovariectomized, estrogen-treated females show greater levels of adenohypophyseal vasoinhibins than males. Peptide sequencing analysis revealed that the cleaved form of PRL in rat adenohypophyseal extracts contains the PRLN terminus and a second N terminus starting at Ser149, the reported cleavage site of cathepsin D in rat PRL. In addition, cathepsin D inhibition by pepstatin A reduced vasoinhibin levels in rat adenohypophyseal cell cultures. Confocal and electron microscopy showed the colocalization of cathepsin D and PRL within rat adenohypophyseal cells and secretory granules, and a subcellular fraction of rat adenohypophysis enriched in secretory granules contained cathepsin D activity able to generate vasoinhibins from PRL. Of note, vasoinhibins were absent in the adenohypophysis of mice lacking the cathepsin D gene but not in wild-type mice. These findings show that cathepsin D is the main protease responsible for the generation of adenohypophyseal vasoinhibins and that its action can take place within the secretory granules of lactotrophs. Copyright © 2009 by The Endocrine Society.
Filiaciones:
Cruz-Soto M.E.:
UNAM, Inst Neurobiol, Queretaro 76230, Mexico
Cosío G.:
UNAM, Inst Neurobiol, Queretaro 76230, Mexico
Jeziorski M.C.:
UNAM, Inst Neurobiol, Queretaro 76230, Mexico
Vargas-Barroso V.:
UNAM, Inst Neurobiol, Queretaro 76230, Mexico
Aguilar M.B.:
UNAM, Inst Neurobiol, Queretaro 76230, Mexico
Cárabez A.:
UNAM, Inst Neurobiol, Queretaro 76230, Mexico
Berger P.:
Austrian Academy of Science, Institute for Biomedical and Aging Research, A-6020 Innsbruck, Austria
Saftig P.:
Department of Biochemistry, University of Kiel, D-24098 Kiel, Germany
Arnold E.:
UNAM, Inst Neurobiol, Queretaro 76230, Mexico
Thebault S.:
UNAM, Inst Neurobiol, Queretaro 76230, Mexico
De La Escalera G.M.:
UNAM, Inst Neurobiol, Queretaro 76230, Mexico
Clapp C.:
UNAM, Inst Neurobiol, Queretaro 76230, Mexico
Bronze
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