生物
肌球蛋白
细胞生物学
粘液菌
吞噬作用
肌动蛋白
动力素
伪足
Profilin公司
生物物理学
生物化学
内吞作用
肌动蛋白细胞骨架
细胞骨架
细胞
基因
作者
Régis Dieckmann,Yosuke von Heyden,Claudia Kistler,Navin Gopaldass,Stéphanie Hausherr,Scott W. Crawley,Eva C. Schwarz,Ralph P. Diensthuber,Graham P. Côté,Georgios Tsiavaliaris,Thierry Soldati
标识
DOI:10.1091/mbc.e09-06-0485
摘要
Actin dynamics and myosin (Myo) contractile forces are necessary for formation and closure of the phagocytic cup. In Dictyostelium, the actin-binding protein Abp1 and myosin IK are enriched in the closing cup and especially at an actin-dense constriction furrow formed around the neck of engulfed budded yeasts. This phagocytic furrow consists of concentric overlapping rings of MyoK, Abp1, Arp3, coronin, and myosin II, following an order strikingly reminiscent of the overall organization of the lamellipodium of migrating cells. Mutation analyses of MyoK revealed that both a C-terminal farnesylation membrane anchor and a Gly-Pro-Arg domain that interacts with profilin and Abp1 were necessary for proper localization in the furrow and efficient phagocytosis. Consequently, we measured the binding affinities of these interactions and unraveled further interactions with profilins, dynamin A, and PakB. Due to the redundancy of the interaction network, we hypothesize that MyoK and Abp1 are restricted to regulatory roles and might affect the dynamic of cup progression. Indeed, phagocytic uptake was regulated antagonistically by MyoK and Abp1. MyoK is phosphorylated by PakB and positively regulates phagocytosis, whereas binding of Abp1 negatively regulates PakB and MyoK. We conclude that a MyoK-Abp1-PakB circuit acts as a switch regulating phagocytosis efficiency of large particles.
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