Calcium Switches Mitochondrial Motors to Drive Filopodia and Cell Migration

When A431 carcinoma cells are stimulated with epidermal growth factor (EGF), their mitochondria fragment into smaller, highly mobile organelles that are actively transported toward the cell’s leading edge and into filopodia, the actin-rich protrusions involved in cell movement. That coordinated remodeling is the central finding of a study published open access in Cellular and Molecular Life Sciences, which traces the repositioning to a calcium-controlled switch between two motor proteins. The work builds on the research team’s earlier demonstration that Myo19-dependent mitochondrial motility is coupled to filopodia formation under stress, and now extends the connection to growth-factor signaling and collective cell migration in cell culture.

The study identifies a division of labor between Kif5B, a microtubule-based kinesin motor, and Myo19, an actin-based myosin motor that carries mitochondria. Under EGF stimulation, cytosolic calcium rises, and this signal has opposite effects on the two motors: it impairs Kif5B-mediated motility while enhancing Myo19 activity. The consequence is a shift of mitochondrial trafficking predominantly onto the actin cytoskeleton, the same filament network that drives protrusion formation. Live-cell imaging captured the sequence in action, revealing coordinated mitochondrial motility that involves sequential fission events, switching between the two motor proteins, and localized calcium signaling at protrusion sites.

The remodeling appears to be functionally important rather than incidental. When the researchers disrupted mitochondrial fission or lowered intracellular calcium, mitochondrial motility was severely impaired and filopodia formation dropped significantly. In the same cells, EGF stimulation suppressed proliferation while promoting calcium signaling and cytoskeletal remodeling, an observed pairing of reduced division with increased motility-associated remodeling. Together, these experiments indicate that delivering remodeled mitochondria to the cell periphery depends on both the fission process and the calcium signal that reroutes transport onto actin tracks.

To test Myo19’s role in a broader cellular context, the researchers performed two-dimensional wound-healing assays using Myo19-knockdown cell lines. Myo19 depletion severely impaired wound closure across several cell lines, indicating that Myo19-driven remodeling of the mitochondrial network at the leading edge and in filopodia contributes to collective cell migration. The authors propose that this mechanism links mitochondrial dynamics and motility to actin cytoskeletal remodeling and the formation of cellular protrusions, and they suggest that Myo19’s strong connection to cell migration could inform therapeutic strategies targeting mitochondrial-cytoskeletal interactions during metastasis. As with any cell-culture study, translating these findings to tumors in living organisms will require further investigation. Even so, the identification of a calcium-gated motor switch provides a concrete molecular handle on how cells position their mitochondria to support movement, and it marks Myo19 as a candidate worth testing in models of invasive behavior.

Subject of Research: Calcium-regulated mitochondrial trafficking by Myo19 in filopodia formation and cell migration

Article Title: Calcium-regulated mitochondria remodeling by Myo19 is required for filopodia tip-extension and supports collective cell migration

Article References: Li, S., Shneyer, B. I., Elisha, D., Trestin-Volt, A., & Henn, A. (2026). Calcium-regulated mitochondria remodeling by Myo19 is required for filopodia tip-extension and supports collective cell migration. Cellular and Molecular Life Sciences. https://doi.org/10.1007/s00018-026-06420-w

Image Credits: AI Generated

DOI: 10.1007/s00018-026-06420-w

Keywords: mitochondria, Myo19, Kif5B, calcium signaling, filopodia, cell migration, EGF, cytoskeleton, mitochondrial fission, A431 carcinoma cells, metastasis, cell biology