Phagocytosis consists in ingestion and digestion of large particles, a process strictly dependent on actin re-organization. Using synchronized phagocytosis of IgG-coated latex beads (IgG-LB), zymosan or serum opsonized-zymosan, we report the formation of actin structures on both phagocytic cups and closed phagosomes in human macrophages. Their lifespan, size, protein composition and organization are similar to podosomes. Thus, we called these actin structures phagosome-associated podosomes (PAPs). Concomitantly to the formation of PAPs, a transient disruption of podosomes occurred at the ventral face of macrophages. Similarly to podosomes, which are targeted by vesicles containing proteases, the presence of PAPs correlated with the maturation of phagosomes into phagolysosomes. The ingestion of LB without IgG did not trigger PAPs formation, did not lead to podosome disruption and maturation to phagolysosomes, suggesting that these events are linked together. Although similar to podosomes, we found that PAPs differed by being resistant to the Arp2/3 inhibitor CK666. Thus, we describe a podosome subtype which forms on phagosomes where it probably serves several tasks of this multifunctional structure.

吞噬作用包括大颗粒的摄取和消化，这是一个严格依赖肌动蛋白重组的过程。使用 IgG 包被的乳胶珠 (IgG-LB)、酵母聚糖或血清调理酵母聚糖的同步吞噬作用，我们报告了人类巨噬细胞中吞噬杯和封闭吞噬体上肌动蛋白结构的形成。它们的寿命、大小、蛋白质组成和组织类似于足体。因此，我们将这些肌动蛋白结构称为吞噬体相关足小体 (PAP)。伴随着 PAP 的形成，在巨噬细胞的腹面发生了足体的短暂破坏。与被含有蛋白酶的囊泡靶向的足体类似，PAP 的存在与吞噬体成熟为吞噬溶酶体相关。摄入不含 IgG 的 LB 不会触发 PAPs 的形成，没有导致足体破坏和成熟为吞噬溶酶体，表明这些事件是联系在一起的。尽管与足体相似，但我们发现 PAP 的不同之处在于对 Arp2/3 抑制剂 CK666 具有抗性。因此，我们描述了一种在吞噬体上形成的足体亚型，它可能为这种多功能结构的几个任务服务。