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eIF4E and Ezrin cooperate in pseudopods to drive a localized migratory translation program in acute myeloid leukemia

Biljana ČuljkovićiD, Leandro Marcelo MartineziD, Naiyu Shi, Alyssa D. RetiziD, Samuel Perron, Aksharh Thambipillai, Caleb M. EmbreeiD, Winnie Yip, Vicenta Trujillo-AlonsoiD, Emma Lassman, Marysol Chu CartyiD, Kata AliloviciD, Sébastien CarrenoiD, Gail J. RoboziD, Mónica L. GuzmániD, Katherine L. B. BordeniD

Abstract

eIF4E, the mRNA cap-binding protein, is elevated in acute myeloid leukemia (AML) subtypes associated with increased cell movement and leukemic infiltration. We show here that eIF4E is required for AML cell motility, bone marrow engraftment, and disease progression in mouse models, patient specimens and cell line models. While dissecting the underlying mechanisms of eIF4E-dependent motility, we discovered that the motility factor Ezrin, enriched in pseudopods, is required for high-eIF4E AML cell movement. We discovered that eIF4E directly binds Ezrins FERM domain and that Ezrin, through this direct interaction with eIF4E, associated with mRNAs encoding its own motility pathway. We developed a method to directly mark active ribosomes in situ (VISTA-R) allowing us to observe translation in Ezrin-positive pseudopods. We show that Ezrin anchors actively translating ribosomes in pseudopods, creating a localized translation site we term a T-POD. Depleting Ezrin reduced the number of active ribosomes within T-PODs, without affecting global translation; and Ezrin reduction was sufficient to decrease protein production of factors in the Ezrin-CD44-HA motility pathway corresponding to impaired motility, positioning Ezrin not only as a motility factor but also now as a positive regulator of translation. Furthermore, Ezrin RIP-seq data revealed that Ezrin, through eIF4E, potentially regulates production of many factors involved in invasion including cytoskeletal remodeling and protrusion formation and extracellular matrix remodeling. In all, our studies identify an unanticipated role for Ezrin in a local translation program that sustains AML motility in vivo through provisioning T-PODs and revealed an unexpected direct connection between the translation and motility machinery.

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Claude Opus 5.5 · xhigh effort · 7 Nov 2026 · from the full text of version 3 (2 Oct 2026) · CC BY 4.0

In acute myeloid leukemia, Ezrin binds eIF4E and anchors active ribosomes in pseudopods for local translation of CD44 and hyaluronan pathway proteins; eIF4E loss impairs mouse engraftment.

The paper says it was unclear whether post-transcriptional control contributes to leukemic cell movement, and whether translation is spatially coordinated with the motility machinery. It introduces VISTA-R, which labels active ribosomes in fixed cells instead of newly made proteins that diffuse away within seconds.

Key results

  1. ShowneIF4E levels set AML cell adhesion, invasion, marrow engraftment and survival. Overexpression raised adhesion and invasion; CRISPR knockdown lowered them and prolonged survival in xenografts.

    Roughly 2-fold changes in adhesion and invasion in either direction. MM6 CRISPR-4E vs control marrow engraftment 10.13 ± 2.78% (n=10) vs 56.53 ± 4.98% (n=10), p<0.0001. Overall survival 48 vs 37 days (MM6) and 86 vs 59 days (THP-1, p=0.0002). · eIF4E drives AML cell migration, infiltration…

  2. SuggestedThe eIF4E inhibitor ribavirin reduced invasion of primary high-eIF4E AML specimens ex vivo and extended survival in one patient-derived xenograft model.

    Invasion fell about 2- to 3-fold in AML55 and AML23 (p=0.0158, 0.0123). In AML55 PDX mice (n=5 per arm), median survival was 189 days with ribavirin vs 138 days with saline (p=0.0384). · Pharmacological targeting of eIF4E and motility

  3. ShownEzrin is needed for AML motility, and high-eIF4E cells depend on it more. Ezrin's FERM domain binds eIF4E directly, and the interaction does not depend on RNA.

    Ezrin siRNA cut adhesion about 2-fold and invasion about 1.5-fold. Invasion of CRISPR-4E cells was unaffected, vs a 30-40% drop in control cells. Purified GST-FERM pulled down eIF4E; RNase did not disrupt the Ezrin-eIF4E co-IP. · A novel interplay between the motility and…

  4. ShownVISTA-R signal shows active ribosomes in Ezrin-rich pseudopods (T-PODs). Ezrin or eIF4E knockdown reduces ribosome and rRNA content per T-POD, while Ezrin knockdown leaves global protein synthesis unchanged.

    Puromycin or homoharringtonine cut VISTA-R signal about 2-fold. Ezrin overlapped eIF4E 0.925, VISTA-R 0.825, rRNA 0.791. Ezrin knockdown lowered VISTA-R 2-fold and rRNA 2.4-fold per T-POD; eIF4E knockdown lowered them 1.5- and 1.9-fold. · Active ribosomes are found in pseudopods; Translation in T-PODs is Ezrin- and…

  5. SuggestedEzrin associates with mRNAs of its own CD44/hyaluronan pathway, and its knockdown lowers their protein levels without changing mRNA levels. A suspension-cell RIP-seq suggests a wider set of motility-related targets.

    In invaded cells, Ezrin RIP gave 2-4-fold enrichment for CD44, EZR, HAS3 and HK2 mRNAs. Ezrin siRNA lowered CD44, HAS3, HK2, PGM5 and UAP1 protein by about 40-60%. RIP-seq found 335 enriched transcripts (fold change >1.5, adjusted p<0.05). · Ezrin physically associated with transcripts…

Methods, data and reproducibility

The authors changed eIF4E or Ezrin levels (overexpression, CRISPR, siRNA) in human AML lines and measured invasion, adhesion, spheroid colonization and xenograft engraftment. They mapped Ezrin-eIF4E-ribosome interactions by co-IP, RIP and pulldowns, and developed VISTA-R imaging, quantified with Imaris, to localize active ribosomes.

  • AML cell lines (MM6, THP-1, NOMO-1) and HS-5 stromal line; eIF4E overexpression, CRISPR knockdown and siRNA conditions · human · n = multiple clones and biological replicates; n varies per figure
  • Cell line xenografts in NSG mice (MM6 and THP-1 CRISPR-4E vs control clones) · mouse (NSG mice carrying human cells) · n = n=10 per arm (MM6 4EC6/CTRL7); n=5 to 10 per arm in other cohorts
  • AML55 patient-derived xenograft treated with ribavirin vs saline · mouse (NSG mice with human AML cells) · n = n=5 per arm
  • Primary AML specimens (AML55, AML23, AML13) and healthy donor CD34+ cells · human · n = 3 high-eIF4E specimens
  • Leucegene cohort survival analysis of eIF4E levels · human · n = 609 patients
  • Ezrin RIP-seq of cytoplasmic fractions from MM6 and MM6 CRISPR-CTRL cells in suspension · human · n = MM6 and CRISPR-CTRL cells treated as biological replicates
Methods & tools
VISTA-R, RiboLace 3P puromycin analog, Imaris v10.2, STAR, DESeq2, clusterProfiler, Bowtie2, htseq-count, GENCODE v42, GraphPad Prism 10.6.1, LentiCRISPRv2, Fiji
Reagents & environment
Imaris v10.2, GraphPad Prism 10.6.1, R 4.4.2, GRCh38 with GENCODE v42; no container or requirements file stated.
Reproducibility gaps
No code repository or RIP-seq data accession is given; primers and the RIP-seq enrichment table are in supplementary tables.
Limitations (5)
  • Invaded cells yielded only about 100 µg of material, so RIP in invaded cells was limited to RT-qPCR of selected targets, and RIP-seq was done in suspension cells. · stated by the authors
  • Translation efficiency per transcript in pseudopods could not be measured; the authors infer local translation from Ezrin and eIF4E binding plus protein output. · stated by the authors
  • Differences in fold enrichment between Ezrin and eIF4E RIPs may reflect antibody avidity and cannot be read as differences in affinity. Ezrin anchoring may be direct but may need additional stabilizing factors. · stated by the authors
  • Ezrin was perturbed by siRNA only, with no FERM-binding mutant or rescue, so its translation role is hard to separate from its general motility role. · noted in this summary
  • VISTA-R was validated only by roughly 2-fold signal loss with translation inhibitors, in suspension cells; most mechanistic data are from MM6 cells. · noted in this summary

Who should read:Read this if you study localized translation or cell migration and want a method that marks active ribosomes in fixed cells, or if you care about eIF4E as a target in AML.

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