Table 2.

The dynamic cycle regulated by the Arp2/3 complex.

Regulatory role	Mechanistic class	Factor(s)	Primary target or action	Mechanistic effect
Activation	Class I NPF	WASP/N-WASP and WAVE/SCAR	WCA/VCA regions bind Arp2/3; selected NPFs deliver actin monomers (Higgs and Pollard, 2001; Zimmet et al., 2020; Carlson and Nolen, 2026).	Promote localized branch nucleation; requirements differ among NPF families.
Activation/stabilization	Class II NPF and branch stabilizer	Cortactin	Binds Arp2/3 and branch junctions and cooperates with WASP-family proteins (Uruno et al., 2001; Fregoso et al., 2023).	Enhances nucleation in defined contexts and stabilizes newly formed branches.
Inhibition	Inhibitory NPF	Arpin	Antagonizes Arp2/3 activation by competing with activating nucleation-promoting factors (Cao and Way, 2024).	Dispensable for chemotaxis in the tested model; broader migration effects are context dependent (Dang et al., 2017).
Debranching	Branch-disassembly factors	GMF and coronins, including Coro7	Destabilize branch junctions or promote Arp2/3 release (Guo et al., 2018; Shatery Nejad et al., 2025).	Increase branch turnover and permit network remodeling.
Turnover/renewal	Branch regeneration	Nucleotide exchange on retained Arp2/3	Permits renucleation after load-induced branch dissociation (Ghasemi et al., 2024).	Supports reuse of Arp2/3 at mother filaments under defined conditions.