Figure 9.

Proposed role of cav-1 in Cyr61 signaling in cell proliferation and hyperoxia-induced cell death. This cartoon illustrates Cyr61 signaling involving cav-1/integrin in wild-type and cav-1^−/− cells. Without cav-1/caveolae, Cyr61 is secreted into the cell matrix without any barriers. BFA can block the exocytosis of Cyr61 in cav-1^−/− cells. In wild-type cells, cav-1/caveolae blocks the exocytosis of Cyr61 and mediates the internalization of Cyr61. In cav-1^−/− cells, with elevated secretion, Cyr61 accumulates in extracellular matrix, subsequently functioning via an autocrine or paracrine manner. Increased extracellular Cyr61 continues to stimulate cell proliferation and survival, probably via PI3K/Akt pathways.