Table 1.
Morphological and functional differences between protrusions formed by cells in the 2D and 3D cases
| Type of protrusions | Width (μm) | Length (μm) | Number per cell at any time | Topology | F-actin organization | Arp2/3 | N-WASP | Regulatory role in cell motility |
|---|---|---|---|---|---|---|---|---|
| 2D case | ||||||||
| Lamellipodium | 20–50 | 10 | ∼1 | Thin and wide | Dendritic orthogonal meshwork + bundles | Yes | Yes | Yes |
| Filopodium | <1 | ∼1 | ∼10 | Cylindrical; no dendrites | Single core bundle | No | No | Yes |
| Invadopodia | 0.5–2 | >2 | 10–50 | Short and thin | Actin-associated proteins surround actin core | Yes | Yes | No |
| 3D case | ||||||||
| Mother protrusion | 2.5–10 | 10–60 | ∼1 | Cylindrical | Multiple cortical bundles | Yes | Yes | No |
| First-generation daughter protrusion | 2–5 | 10 | ∼0.5 | Cylindrical; dendrites | Multiple cortical bundles | Yes | Yes | Yes |
Differences in length and lateral dimensions, topology, F-actin organization, and regulatory roles played by lamellipodia-specific proteins Arp2/3 and N-WASP between pseudopodial protrusions formed by cells in 3D matrix and lamellipodial/filipodial/invapodial protrusions formed by the same cells on 2D substrates. Results compare WT HT1080 cells on collagen I-coated substrates and these cells inside a collagen I matrix.