Types of Membrane Protrusions

Different types of membrane protrusions like lamellipodia, filopodia, invadopodia, and blebs are formed during cell migration or invasion.

They vary from each other in their morphological, structural, and functional characteristics and are carefully coordinated by several different molecules and signaling pathways.

Lamellipodia are flat, broad protrusions formed at the leading edge of motile cells such as neurons, and immune cells. They function as a driver during chemotaxis.

Unlike lamellipodia, filopodia are thin, needle-like projections that extend from the leading edge of some migrating cells to help them probe the environment.

In contrast to other types of protrusions, blebs are unique in their appearance and formation.

They are spherical membrane projections formed due to internal hydrostatic pressure in the cells, such as fibroblasts and immune cells.

Blebs are not only functional during migration but also other cellular processes such as apoptosis.

Cancer cells form a special type of protrusion called invadopodia.

Invadopodia are enriched with matrix proteinases that allow the invasive cancer cells to degrade the ECM barrier and spread to other parts of the body.