Caveolae facilitate muscarinic receptor-mediated intracellular Ca2+ mobilization and contraction in airway smooth muscle
| Autor: | Reinoud Gosens, Karol D. McNeill, Johan Zaagsma, Angela Paulson, Helmut Unruh, Gerald L. Stelmack, Mark M. Mutawe, Andrew J. Halayko, James A. Thliveris, Shyamala Dakshinamurti, William T. Gerthoffer, Martha Hinton, Gordon Dueck |
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| Přispěvatelé: | Molecular Pharmacology, Groningen Research Institute for Asthma and COPD (GRIAC) |
| Jazyk: | angličtina |
| Rok vydání: | 2007 |
| Předmět: |
Physiology
Caveolin 1 Respiratory System Intracellular Space PROTEIN ACTIVATION Cytosol Airway resistance Caveolae Caveolin Muscarinic acetylcholine receptor Myocyte RNA Small Interfering Receptor Cells Cultured beta-Cyclodextrins N-Methylscopolamine Cell biology TRANSLOCATION Trachea medicine.symptom G alpha(q) Intracellular Muscle Contraction Muscle contraction Pulmonary and Respiratory Medicine EXPRESSION medicine.medical_specialty SCAFFOLDING DOMAIN Biology PHOSPHOINOSITIDE METABOLISM Tritium MYOCYTES CALCIUM Dogs Physiology (medical) Internal medicine medicine Animals Humans Calcium Signaling G protein-coupled receptor Receptor Muscarinic M3 Muscle Cells Muscle Smooth Cell Biology asthma histamine Acetylcholine Protein Structure Tertiary Endocrinology CELLS GTP-Binding Protein alpha Subunits Gq-G11 caveolin MEMBRANE |
| Zdroj: | American Journal of Physiology-Lung Cellular and Molecular Physiology, 293(6), L1406-L1418. AMER PHYSIOLOGICAL SOC |
| ISSN: | 1522-1504 1040-0605 |
| Popis: | Contractile responses of airway smooth muscle (ASM) determine airway resistance in health and disease. Caveolae microdomains in the plasma membrane are marked by caveolin proteins and are abundant in contractile smooth muscle in association with nanospaces involved in Ca2+homeostasis. Caveolin-1 can modulate localization and activity of signaling proteins, including trimeric G proteins, via a scaffolding domain. We investigated the role of caveolae in contraction and intracellular Ca2+([Ca2+]i) mobilization of ASM induced by the physiological muscarinic receptor agonist, acetylcholine (ACh). Human and canine ASM tissues and cells predominantly express caveolin-1. Muscarinic M3receptors (M3R) and Gαq/11cofractionate with caveolin-1-rich membranes of ASM tissue. Caveolae disruption with β-cyclodextrin in canine tracheal strips reduced sensitivity but not maximum isometric force induced by ACh. In fura-2-loaded canine and human ASM cells, exposure to methyl-β-cyclodextrin (mβCD) reduced sensitivity but not maximum [Ca2+]iinduced by ACh. In contrast, both parameters were reduced for the partial muscarinic agonist, pilocarpine. Fluorescence microscopy revealed that mβCD disrupted the colocalization of caveolae-1 and M3R, but [ N-methyl-3H]scopolamine receptor-binding assay revealed no effect on muscarinic receptor availability or affinity. To dissect the role of caveolin-1 in ACh-induced [Ca2+]iflux, we disrupted its binding to signaling proteins using either a cell-permeable caveolin-1 scaffolding domain peptide mimetic or by small interfering RNA knockdown. Similar to the effects of mβCD, direct targeting of caveolin-1 reduced sensitivity to ACh, but maximum [Ca2+]imobilization was unaffected. These results indicate caveolae and caveolin-1 facilitate [Ca2+]imobilization leading to ASM contraction induced by submaximal concentrations of ACh. |
| Databáze: | OpenAIRE |
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