Back

Phactr4 influences macrophage lamellipodial structure and dynamics through Arp2/3 complex and Ezrin regulation

Manickam, R.; Rotty, J. D.

2025-05-14 cell biology
10.1101/2025.05.13.653717 bioRxiv
Show abstract

Dynamic cycles of actin remodeling drive membrane protrusion and retraction events essential for macrophage function. Phosphoregulation of actin-associated proteins plays a key role, but the factors that determine the spatiotemporal balance between kinases and phosphatases is less well understood in this context. Here, we identify the Protein Phosphatase 1 (PP1)-binding protein Phactr4 as a critical regulator of cytoskeletal remodeling. Phactr4 loss disrupts lamellipodial architecture, which results in uncoordinated migration and disrupted iC3b-mediated phagocytosis. Unstable membrane dynamics underlie the Phactr4 knockdown phenotypes. Phactr4 is recruited to the leading edge via interaction with active Arp2/3 complex, and strongly correlates with membrane retraction. Phactr4 loss leads to ezrin hyperphosphorylation, and membrane protrusion defects in these cells are reversed by ezrin inhibition. Our findings position Phactr4 as a critical PP1-dependent coordinator of cytoskeletal remodeling during macrophage migration and phagocytosis. Recent reports have linked Phactr4 to several human disease states, which may be due to its influence on actin dynamics.

Matching journals

The top 3 journals account for 50% of the predicted probability mass.

50% of probability mass above

"Similar papers" are the closest papers from that journal in the model's embedding space. They show what the match is built on, but the ranking comes mostly from a classifier over the whole training set, not from these examples alone.