Caveolae Facilitate but Are Not Essential for Platelet-Activating Factor-Mediated Calcium Mobilization and Extracellular Signal-Regulated Kinase Activation

摘要: Certain proteins, including receptors and signaling molecules, are known to be enriched in caveolae lipid rafts. Caveolin-1, the major structural protein of caveolae, specifically interacts with many molecules and, thus, rafts often seen as preassembled platforms. A potential binding site for caveolin-1 is present platelet-activating factor receptor (PAFR) sequence, downstream components PAFR activation preferentially localize caveolae. The aim this study was investigate whether localized caveolae/lipid raft domains if so, what would significance such localization signaling. In study, we demonstrate that localizes within membrane microdomains, close proximity living cells, interaction through a caveolin-1-binding sequence C terminus. however, not essential Disruption methyl-β-cyclodextrin markedly reduced PAF-triggered inositol phosphate production cytosolic calcium flux, suggesting Gαq critically dependent on integrity and/or Interestingly, whereas caveolin-1-expressing cells disruption decreased PAFR-mediated ERK/MAPK pathway, lacking leukocytes, had either same inhibitory effect (Ramos B cells) or no (monocytes) capacity signal pathway. conclusion, appears different cell types, location may important specific events.