Cells engulf particles larger than 0.5 μm in diameter by phagocytosis, which is driven by cytoskeletal rearrangements. Phagocytosis by alveolar epithelial cells (AECs) helps to maintain the alveolar homeostasis. Yes-associated protein (YAP), a transcriptional coactivator of the Hippo pathway, affects proliferation, differentiation, and cytoskeletal rearrangement of AECs, but it is not clear whether YAP regulates phagocytosis. In this study, interference with YAP expression inhibited phagocytosis in MLE-12 cells and in primary cultures of AEC. Filopodia formation promoted phagocytosis in AECs, and YAP enhanced filopodia formation in AECs. Blocking PI3K signaling resulted in reduced YAP protein expression and inhibition of phagocytosis. The results indicate that YAP expression was regulated by PI3K signaling and promoted phagocytosis in AECs by upregulating filopodia formation.

细胞通过吞噬作用吞噬直径大于0.5μm的颗粒，这是由细胞骨架重排驱动的。肺泡上皮细胞（AEC）的吞噬作用有助于维持肺泡稳态。Yes-associated protein（YAP）是Hippo通路的转录共激活因子，会影响AEC的增殖，分化和细胞骨架重排，但尚不清楚YAP是否调节吞噬作用。在这项研究中，对YAP表达的干扰抑制了MLE-12细胞和AEC原代培养物中的吞噬作用。丝状伪足的形成促进了AEC中的吞噬作用，而YAP则增强了AEC中的丝状伪足的形成。阻断PI3K信号传导可降低YAP蛋白表达并抑制吞噬作用。