Podosomes are highly dynamic structures with a life-time of 2-12 min. Dynamic behavior of podosomes comprises de novo formation, fission into daughter podosomes and dissolution. In addition, fusion of podosomes has been observed, and there also exists a pool of more static podosomes in a cell.

Podosome dynamics in a primary human macrophage. Image from confocal time lapse movie of a migrating macrophage expressing GFP-actin. Podosome cores are visible as actin-rich dots. White frame indicates detail image below. (Linder and Kopp, J. Cell Science, 2005).

To see dynamic behavior of podosomes, click on the image. (sequence 11.5 min; 1.5 MB)

Dynamic behavior (i.e., fission or dissolution) of podosomes in primary human macrophages is often preceded by contact with microtubule plus ends.

Podosome dynamics and contact by microtubule plus ends.
Large panel:
Image from confocal time lapse movie of primary human macrophage, podosomes visualized by mRFP-labeled actin, microtubule plus ends visualized by GFP-CLIP170. Size bar: 10 µm.
Detail images:
1) a podosome dissolves after contact with microtubule plus ends. Watch movie (sequence 6.6 min, 0.6 MB)
2) a podosome remains static. Watch movie (sequence 6.6 min, 0.8 MB)
3) a large podosome precursor cluster splits into two daughter podosomes. Watch movie (sequence 6.6 min, 1.3 MB)
(Kopp et al., Mol. Biol. Cell, 2006).


Invasion of primary human macrophages into collagen I.
Time lapse video of primary human macrophages embedded in dense collagen I (2.5 mg/ml; dark area on the left), invading into less dense collagen I (2 mg/ml; lighter area on the right), which contains a chemoattractant. White bar scales 41 µm; video starts 9 h after cell seeding. Note mesenchymal morphology of invading cells characterised by numerous elongated protrusions. To see movie, click on the image. (1 image/15 min; frame rate: 10 f/s; sequence: 32 h 15 min; 1.2 MB)

Colocalisation of MT1-MMP-mCherry and GFP-Rab22a in living cells.
Confocal time-lapse video of a primary human macrophage expressing MT1-MMP-mCherry (red) and GFP-Rab22a (green). White bar scales 12 µm; white boxes show simultaneously detailed time lapse, marked within the cell. Note colocalisation of MT1-MMP-mCherry with GFP-Rab22a positive (small or giant) vesicles. To see movie, click on the image. (1 image/2 sec; frame rate: 10 f/s; sequence: 92 s; 397 KB)

Supervillin forms a cap-like structure on top of the podosome core.
3D reconstruction of z-stacks of a single podosome. Cap-like distribution of GFP–SV (green) on top of the F-actin–rich podosome core (red), surrounded by a ring of vinculin (blue). To see movie, click on the image. (sequence 17 sec; 474 KB)

GFP-myosin IIA contacts dissolving podosomes.
Confocal time-lapse video of a macrophage expressing GFP-myosin IIA (green) and mRFP-supervillin (red). Note formation of GFP-myosin IIA-enriched trailing edge and absence of mRFP-supervillin from podosomes at the leading edge (lower right). Contact of GFP-myosin IIA with mRFP-positive podosomes at the rear of the podosome field precedes their disappearance, while podosomes at the forward side of the field acquire mRFP-supervillin. To see movie, click on the image. (sequence 7 sec; 88.4 KB)

Phagocytosis of borreliae by primary human macrophage.
Time-lapse movie of confocal z-stack showing a primary human macrophage expressing RFP-Lifeact (red) internalizing several GFP-expressing spirochetes (green) with actin-rich cell protrusions. To see movie, click on the image. (sequence 41 min; 4.4 MB)

GFP-Daam1C50 enrichment in uptake structure during internalization of Borrelia.
Time lapse movie shows primary macrophage expressing GFP-Daam1DC50 (green) capturing a Borrelia cell stained by Hoechst 33342 (blue). Note GFP-Daam1DC50 accumulations arising from the macrophage surface and closely following the sinuous morphology of the spirochete cell.
Time since the start of the experiment is indicated in minutes. Scale bar 5 µm.