Binds to actin monomers and regulates the organization of the actin cytoskeleton (PubMed:21090759). At high concentrations, profilin prevents the polymerization of actin, whereas it enhances it at low concentrations (PubMed:26996265, PubMed:16313636, PubMed:29861135). At low concentrations, associates with the poly-proline motif of formins to enhance actin filament elongation rate (PubMed:29861135). Binds G-actin and poly-L-proline with low affinity in vitro (PubMed:19200149). Binds ACT1, ACT7 and ACT11 and inhibits actin polymerization (PubMed:26578694). May be involved in the cross-talk between vesicular trafficking and the actin cytoskeleton (PubMed:21090759). At high concentrations, profilin prevents the polymerization of actin, whereas it enhances it at low concentrations (By similarity). Inhibits cell growth of various pathogenic fungal strains (PubMed:30056100). May play a role as antifungal proteins in the defense system against fungal pathogen attacks (PubMed:30056100). Occurs in many kinds of cells as a complex with monomeric actin in a 1:1 ratio. Expressed in vascular bundles of roots, hypocotyls, cotyledons, leaves, sepals, petals, stamen filaments and stalks of developing seeds (PubMed:8771785, PubMed:16361517). Expressed in leaf epidermal cells, trichomes and stem epidermal cells (PubMed:19200149). Detected in phloem exudates (at protein level) (PubMed:30056100). Induced by treatment with brefeldin A. Defects in rosette leaf and inflorescence development. Belongs to the profilin family.