Podosomes are dynamic actin-rich structures that are able to locally degrade the matrix through recruitment of matrix-lytic enzymes; this allows macrophages to cross tissue barriers and navigate through dense extracellular matrix. The podosome core has been shown to contain branched actin filaments that are nucleated by Arp2/3, but recent evidence also suggests the presence of unbranched filaments in podosomes. In their work on page 298, Stefan Linder and colleagues now show that the formins FHOD1 and INF2 localise to different podosome substructures in primary human macrophages. Using a variety of microscopy-based approaches, including a podosome reformation assay, they find that the two formins regulate different aspects of podosomes. INF2 localises to the podosome cap structure; it negatively regulates podosome size and positively affects podosomal matrix degradation. Because INF2 also regulates podosome oscillations, it most probably also plays a role in the mechanosensing ability of podosomes. FHOD1 depletion did not lead to any significant changes in overall podosome size or number, but reduced actomyosin contractility at podosome-connecting actin cables, suggesting that FHOD1 functions to regulate podosome connectivity, possibly to establish the typical regular podosome pattern at the substrate-contacting cell side. Taken together, these findings not only establish formins as new regulators of podosome function, but also highlight that these structures represent an excellent model system for the analysis of complex actin architectures in cells.
Formins help podosomes form Free
Formins help podosomes form. J Cell Sci 15 January 2016; 129 (2): e0201. doi:
Download citation file:
Advertisement
Cited by
Special Issue – Cell Biology of Mitochondria

Our special issue on ‘Cell Biology of Mitochondria’ is now complete. Explore this issue and read the Editorial from our Guest Editors Ana J. García-Sáez and Heidi McBride.
Save the date – Imaging Cell Dynamics

We are delighted to announce that we will be hosting a 2026 Imaging Cell Dynamics meeting. This meeting will provide a unique opportunity to bring together experts working at the interface between cell biology and imaging. Save the date for 11-14 May 2026 and register for more information.
Mitochondria–membranous organelle contacts at a glance

Antigoni Diokmetzidou and Luca Scorrano provide an overview of contacts between mitochondria and other membranous organelles, describing the interorganelle tethers involved and the factors that regulate the composition and functions of such contacts.
JCS-FocalPlane Training Grants

Early-career researchers - working in an area covered by JCS - who would like to attend a microscopy training course, please apply. Deadline dates for 2025 applications: 6 June 2025 (decision by week commencing 28 July 2025) and 5 September 2025 (decision by week commencing 20 October 2025).
JCS fast-track option

Have a paper that has been reviewed elsewhere? JCS is pleased to consider such manuscripts for fast-tracked decision making. Send us your manuscript together with the full set of reviews and decision letters, and we will make an initial decision within one week.
Help shape your future publishing experience

We are gathering feedback from our readers, authors and reviewers, to help us shape the next 100 years and to keep offering a publishing experience that truly supports our community. Please have your say by completing our community survey. Survey closes on 25 June.