title: Signaling pathways between the plasma membrane and endoplasmic reticulum calcium stores.
abstract: This review discusses multiple ways in which the endoplasmic reticulum participates in and is influenced by signal transduction pathways. The endoplasmic reticulum provides a Ca2+ store that can be mobilized either by calcium-induced calcium release or by the diffusible messenger inositol 1,4,5-trisphosphate. Depletion of endoplasmic reticulum Ca2+ stores provides a signal that activates surface membrane Ca2+ channels, a process known as capacitative calcium entry. Depletion of endoplasmic reticulum stores can also signal long-term cellular responses such as gene expression and programmed cell death or apoptosis. In addition to serving as a source of cellular signals, the endoplasmic reticulum is also functionally and structurally modified by the Ca2+ and protein kinase C pathways. Elevated cytoplasmic Ca2+ causes a rearrangement and fragmentation of endoplasmic reticulum membranes. Protein kinase C activation reduces the storage capacity of the endoplasmic reticulum Ca2+ pool. In some cell types, protein kinase C inhibits capacitative calcium entry. Protein kinase C activation also protects the endoplasmic reticulum from the structural effects of high cytoplasmic Ca2+. The emerging view is one of a complex network of pathways through which the endoplasmic reticulum and the Ca2+ and protein kinase C signaling pathways interact at various levels regulating cellular structure and function.
authors.affiliation: Calcium Regulation Section, Laboratory of Signal Transduction, National Institute of Environmental Health Sciences-NIH, Research Triangle Park, North Carolina 27709, USA. putney@niehs.nih.gov
authors.forename: J W
authors.initials: JW
authors.lastname: Putney
authors.forename: C M
authors.initials: CM
authors.lastname: Ribeiro
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling / Q000502:physiology*; D002462:Cell Membrane / Q000502:physiology*; D004721:Endoplasmic Reticulum / Q000502:physiology*; D006801:Humans
chemical_list: D002118:Calcium