Chapter category: Cell Metabolism

Adaptation of the Secretory Machinery to Pathophysiological Conditions

This chapter appears in the following book:

Molecular Mechanisms of Exocytosis

Edited by: Romano Regazzi
ISBN: 0-387-39960-7
» Get more information about this book at landesbioscience.com «

Chapter authors:
Abderrahmani Amar

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Regulated exocytosis is a fundamental and common feature of all secretory cells specialized in the release of essential bioactive substances. This process is tightly controlled to adapt the amount of released products in response to the variable physiological cues. However it occurs that inadequate, excessive and/or prolonged exposure to environmental demands become stressful and desensitizes or irreversibly damage the cell secretory competence. The insulin-releasing b-cells of the islets of Langerhans represent a well characterized model of adaptation of the secretory response. In this system, while physiological elevation of glucose or lipids concentration can acutely stimulate insulin release, prolonged exposure to these secretagogues can have deleterious effects on the cells contributing to severe insulin secretion defects in diabetic patients. New emerging data provide evidence that prolonged exposure to elevated glucose concentration is associated with a reduction in the expression of a set of genes essential for exocytosis. This chapter discusses this phenomenon, which occurs at transcriptional levels and leads to a decline in the secretory function. These glucose effects appear to be mediated by a sustained rise in cAMP levels, which in turn induces expression of the inducible cAMP early repressor (ICER), a transcription factor known to be activated in response to stress. Based on these findings, this chapter highlights the role of ICER in the control of the exocytotic apparatus challenged with a stressful environment.

Abderrahmani Amar
Service of Internal Medicine and Department of Cell Biology and Morphology

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Chapter category: Cell Metabolism

Adaptation of the Secretory Machinery to Pathophysiological Conditions

Additional chapters from this book:

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