ACTN4 protein target disrupts iron recycling and triggers ferroptosis in leukemia cells

A new study published in Cellular & Molecular Biology Letters reports that pseudolaric acid B, a natural compound, binds directly to the cytoskeletal protein alpha-actinin-4 (ACTN4) in acute myeloid leukemia cells, setting off a chain of events that culminates in ferroptosis, an iron-dependent form of regulated cell death. The finding, published online on 2 October 2026 as an open-access research article, points to a previously underexplored layer of ferroptosis control: the physical trafficking machinery that decides where iron-importing receptors sit on the cell surface.

Ferroptosis has mostly been studied at the metabolic level, as a death process driven by iron-catalyzed lipid peroxidation. The authors of the new work argue that the cytoskeleton-dependent transport of proteins within the cell has received far less attention, and their results suggest it may be a decisive upstream control point. Using chemical proteomics to identify the protein targets of pseudolaric acid B, the team found that ACTN4, an actin-crosslinking protein, was a direct target of the compound.

The interaction was validated with several independent approaches. A cellular thermal shift assay and a drug affinity responsive target stability assay both supported binding between the compound and ACTN4, and biophysical assays and mutagenesis were used to characterize the engagement further. The researchers identified lysine 273, a residue within ACTN4’s actin-binding domain, as a site modified by a PAB-biotin probe, and mutational analysis implicated this residue in the compound’s binding to the protein.

Functionally, the consequences of that binding were traced through the cell’s structural and trafficking systems. The interaction between PAB and ACTN4 disrupts the association between ACTN4 and filamentous actin, the polymerized form of the protein that gives cells their shape and organizes internal transport routes. This disruption leads to cytoskeletal instability and impaired endosomal trafficking, the vesicle-based shuttle system that moves receptors between the cell surface and internal compartments.

One receptor proved especially consequential: transferrin receptor 1, or TfR1, the main gateway through which cells import iron bound to transferrin. When endosomal trafficking faltered, TfR1 accumulated inside the cell instead of being recycled back to the plasma membrane. The study reports that this mislocalization promotes iron overload and lipid peroxidation, the two ingredients required for ferroptotic cell death.

The causal chain was tested in both directions. When the researchers mutated ACTN4 at position K273, the mutation reduced PAB binding and attenuated iron accumulation, supporting the residue’s role in the compound’s effect. Conversely, when the team stabilized filamentous actin pharmacologically, the receptor’s distribution was restored and the iron imbalance was partially rescued, indicating that the cytoskeletal defect lies upstream of the iron phenotype rather than downstream of it.

Ferroptosis inhibitors told a complementary story. These inhibitors suppressed lipid peroxidation in the treated cells, but they did not correct the underlying cytoskeletal defects. In other words, blocking the cell-death endpoint does not repair the trafficking failure that set it in motion, which the authors interpret as evidence that cytoskeletal dysfunction acts upstream of ferroptosis in this pathway.

The authors conclude that pseudolaric acid B targets ACTN4 and disrupts cytoskeletal integrity, impairing TfR1 trafficking and promoting iron accumulation in acute myeloid leukemia cells. They frame the work as supporting a role for ACTN4 in ferroptosis-associated iron handling and as identifying an ACTN4–TfR1 trafficking axis involved in PAB-induced ferroptotic responses in these leukemia cells.

As with any early-release study, some caveats apply. The article is being shared ahead of final production as a peer-reviewed, accepted manuscript carrying a permanent DOI, and the published version remains subject to further edits. The reported findings are based on cellular and molecular experiments described in the paper’s methods, and the authors present them as evidence for a mechanism in AML cells rather than as demonstrated clinical outcomes. Even so, the study adds a specific molecular handle—ACTN4, its lysine 273 residue, and the recycling route of TfR1—to the growing map of how iron homeostasis is governed when cells die by ferroptosis.

Subject of Research: How the compound pseudolaric acid B targets the cytoskeletal protein ACTN4 to disrupt transferrin receptor recycling and trigger ferroptosis in acute myeloid leukemia cells.

Article Title: Targeting of ACTN4 disrupts cytoskeletal control of TfR1 recycling and drives ferroptosis in acute myeloid leukemia

Article References: Chen, Z., Liao, W., Lu, Q., Chen, J., Yin, Z., Rong, J., Wang, C., Xie, Y., Li, C., Gao, M., Li, L., Li, J., Dai, X., Li, L., Gao, L., Zhao, J., & Qi, H. (2026). Targeting of ACTN4 disrupts cytoskeletal control of TfR1 recycling and drives ferroptosis in acute myeloid leukemia. Cellular & Molecular Biology Letters. https://doi.org/10.1186/s11658-026-01028-1

Image Credits: AI Generated

DOI: 10.1186/s11658-026-01028-1

Keywords: ferroptosis, ACTN4, acute myeloid leukemia, transferrin receptor 1, cytoskeleton, pseudolaric acid B, endosomal trafficking, iron homeostasis, lipid peroxidation, chemical proteomics, Targeting, disrupts