The role of caveolae in regulating calcitonin receptor-like receptor subcellular distribution in vascular smooth muscle cells

To determine whether caveolae and caveolin-1 affect the distribution of calcitonin receptor-like receptors (CLR) in vascular smooth muscle cell (VSMC) membranes, we have used VSMCs cell line A10. We found that calcitonin gene-related peptide (CGRP) reduced CLR protein in the VSMC membrane in a time-dependent manner, which was dramatically decreased after 4 h CGRP treatment, and remained at a low level after 16 h. CGRP8-37 or β-cyclodextrin (β-CD) blocked this effect, without changing the total levels of CLR protein and mRNA in the cells. Co-immunoprecipitation experiments showed that CLR bound to caveolin-1 in cell membrane fractions. Confocal laser microscopic studies confirmed this co-localization relationship at the cell plasma membrane. Thus, our data indicate that the structural integrity of caveolae plays an important role in regulating subcellular distribution of CLR.