Arpin Regulates Migration Persistence by Interacting with Both Tankyrases and the Arp2/3 Complex

Abstract

During cell migration, protrusion of the leading edge is driven by the polymerization of Arp2/3-dependent branched actin networks. Migration persistence is negatively regulated by the Arp2/3 inhibitory protein Arpin. To better understand Arpin regulation in the cell, we looked for its interacting partners and identified both Tankyrase 1 and 2 (TNKS) using a yeast two-hybrid screening and coimmunoprecipitation with full-length Arpin as bait. Arpin interacts with ankyrin repeats of TNKS through a C-terminal-binding site on its acidic tail, which overlaps with the Arp2/3-binding site. Arpin was found to dissolve the liquid–liquid phase separation of TNKS upon overexpression. To uncouple the interactions of Arpin with TNKS and Arp2/3, we introduced point mutations in the Arpin tail and attempted to rescue the increased migration persistence of the Arpin knockout cells using random plasmid integration or compensating knock-ins at the ARPIN locus. Arpin mutations impairing interactions with either Arp2/3 or TNKS were insufficient to fully abolish Arpin activity. Only the mutation that affected both interactions rendered Arpin completely inactive, suggesting the existence of two independent pathways, whereby Arpin controls the migration persistence.

Vinculin-Arp2/3 Interaction Inhibits Branched Actin Assembly to Control Cell Migration and Cell Cycle Progression

“…We previously established that cell cycle progression in untransformed cells depends on cortical branched actin (Molinie et al, 2019). In fact, the Arp2/3-dependent functions of vinculin uncovered here, membrane protrusions, persistence of single cell migration and cell cycle progression, were previously shown to depend on the RAC1-WAVE-Arp2/3 pathway (Dang et al, 2013;Molinie et al, 2019;Simanov et al, 2021). Increased protrusions, increased persistence and increased cycling observed in KO and KI MCF10A cells are phenotypes, which are all associated with increased branched actin, showing that the vinculin-Arp2/3 interaction should antagonize the formation of branched actin.…”

“…We first examined the interaction of vinculin with the Arp2/3 complex in the MCF10A cell line, where we have characterized the role of the Arp2/3 complex in cell migration (Molinie et al , 2019; Simanov et al , 2021). MCF10A cells are human mammary epithelial cells, which are immortalized but not transformed (Soule et al , 1990).…”

A Shape Sensing Mechanism driven by Arp2/3 and cPLA2licenses Dendritic Cells for Migration to Lymph Nodes in Homeostasis

“…ARP2/3 deficiency has been shown to regulate immune cell migration and chemotaxis ex vivo and in vivo (48; 49; 50; 51). We therefore assessed whether Arpin KO DCs displayed enhanced chemotactic migration along CCL19 gradients in collagen gels, as this could also account for their increased migration to lymph nodes at steady state.…”

Regulation of Biomolecular Condensates by Poly(ADP-ribose)

“…62 Indeed, recent evidence suggests that PARP5a undergoes PAR-independent condensation, 34 although PAR may enhance the degree of PS. In cells, PS of PARP5a/b may enable actin cytoskeletal branching by competing with Arp2/3 for binding to Arpin, 321 which antagonizes Arp2/3-mediated branching. 322,323 Indeed, PARP5a localizes to the mitotic spindle and is required for proper cytoskeletal polymerization during mitosis.…”

“…Indeed, recent evidence suggests that PARP5a undergoes PAR-independent condensation, although PAR may enhance the degree of PS. In cells, PS of PARP5a/b may enable actin cytoskeletal branching by competing with Arp2/3 for binding to Arpin, which antagonizes Arp2/3-mediated branching. , Indeed, PARP5a localizes to the mitotic spindle and is required for proper cytoskeletal polymerization during mitosis. ,− PARP5a is also required for the separation of telomeres during mitosis. , Given recent reports that PS occurs at telomeres, PARP5a activity may regulate the condensation at telomeres through PARylation. , A direct link between PARP5a-dependent PARylation, PS of PARP5a, and regulation of cytoskeletal activity has not yet been made.…”