Endothelial Ca2+ waves preferentially originate at specific loci in caveolin-rich cell edges
AUTOR(ES)
Isshiki, Masashi
FONTE
The National Academy of Sciences
RESUMO
Stimulation of endothelial cells (ECs) with ATP evoked an increase in intracellular Ca2+ concentration ([Ca2+]i). In a single bovine aortic EC, the [Ca2+]i rise started at a specific peripheral locus and propagated throughout the entire cell as a Ca2+ wave. The initiation locus was constant upon repeated stimulation with ATP or other agonists (bradykinin and thrombin). The Ca2+ wave was unaffected by the removal of extracellular Ca2+, demonstrating its dependence on intracellular Ca2+ release. Microinjection of heparin into the cell inhibited the ATP-induced Ca2+ responses, indicating that the Ca2+ wave is at least partly mediated by the inositol 1,4,5-trisphosphate receptor. Immunofluorescence staining revealed that caveolin, a marker protein for caveolae, is distributed heterogeneously in the cell and that Ca2+ waves preferentially originate at caveolin-rich cell edges. In contrast to caveolin, internalized transferrin and subunits of the clathrin-associated adaptor complexes such as adaptor protein-1 and -2 were diffusely distributed. Disruption of microtubules by Colcemid led to redistribution of caveolin away from the edges into the perinuclear center of the cell, and the ATP-induced [Ca2+]i increase was initiated on the rim of the centralized caveolin. Thus, caveolae may be involved in the initiation of ATP-induced Ca2+ waves in ECs.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=20204Documentos Relacionados
- Local Ca2+ transients (Ca2+ sparks) originate at transverse tubules in rat heart cells.
- On the roles of Ca2+ diffusion, Ca2+ buffers, and the endoplasmic reticulum in IP3-induced Ca2+ waves.
- Properties of intracellular Ca2+ waves generated by a model based on Ca(2+)-induced Ca2+ release.
- Membrane voltage initiates Ca2+ waves and potentiates Ca2+ increases with abscisic acid in stomatal guard cells
- Endothelial cell Ca2+ increases upon tumor cell contact and modulates cell-cell adhesion.