Fecha de publicación: -- Fuente: PubMed "pollen" Nat Plants. 2026 Oct;12(10):2089-2107. doi: 10.1038/s41477-026-02427-0. Epub 2026 Oct 16.ABSTRACTThe intersection of actin filaments with the plasma membrane (PM) in plant cells involves lipid-protein interactions by the Arabidopsis class VIII myosin ATM2 that are currently not understood. Using pollen tube cells as a model, we describe how ATM2 enables actin-PM contacts by modulating membrane lipid nano-organization. ATM2 bound anionic PM lipids, including phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2), with no apparent preference for any particular lipid species. Overexpression of ATM2 unexpectedly stabilized actin dynamics and altered pollen tube morphology. Actin dynamics remained unaltered upon overexpression of a lipid-binding-defective ATM2 variant. ATM2 effects on actin dynamics required PtdIns(4,5)P2, as artificial PtdIns(4,5)P2 depletion in pollen tubes abolished the effects of full-length ATM2 on actin dynamics despite its retained PM association. ATM2 colocalized and interacted with the PI4P 5-kinase PIP5K2, which resides at actin-PM contacts and forms PtdIns(4,5)P2 nanodomains facilitating rho-of-plants-dependent actin stabilization. Upon ATM2 overexpression, a fluorescent PtdIns(4,5)P2 biosensor decorated an extended PM region in vivo, indicating a promoting effect of ATM2 on PtdIns(4,5)P2 abundance. The catalytic activity of purified recombinant PIP5K2 protein was enhanced upon coincubation with a purified carboxy-terminal ATM2 fragment in vitro, suggesting that ATM2 contributes to the intrinsic regulation of PtdIns(4,5)P2 formation. Actin dynamics are thus stabilized at the actin-PM interface by ATM2 locally promoting the formation of PtdIns(4,5)P2 nanodomains, thereby self-reinforcing ATM2 recruitment while also facilitating rho of plants activation to stabilize membrane-proximal actin filaments.PMID:42888236 | DOI:10.1038/s41477-026-02427-0