Table 1.

Common and unique features of focal adhesions, podosomes, and invadopodia. See text for details.

	Focal adhesion	Podosomes	Invadopodia
Appearance	dense plaques of F-actin	F-actin bundle core surrounded by actin cloud	F-actin bundle core surrounded by actin cloud
Size	width: 2–6 μm	width: 0.5–2 μm length: 0.5–2 μm	width: 0.5–2 μm length: >2 μm
Duration (half-life)	hours	minutes	hours
Cell expression	numerous nonmigrating fibroblastic cells	monocytic cells osteoclasts endothelial cells smooth muscle cells Src-transformed fibroblasts	carcinoma cells Src-transformed fibroblasts
Location	often found at leading edge of cell	ventral side of the cellular membrane	ventral side of the cellular membrane
Extracellular matrix degradation	no	yes	yes
Common signaling molecules	focal adhesion proteins GTPases actin regulators motor proteins tyrosine kinases phosphatases scaffolding molecules	focal adhesion proteins GTPases actin regulators motor proteins tyrosine kinases phosphatases scaffolding molecules	focal adhesion proteins GTPases actin regulators motor proteins tyrosine kinases phosphatases scaffolding molecules
Distinct Features	integrin receptors	Integrin receptors matrix-degrading enzymes	matrix-degrading enzymes