Model invasive structures. Left: detailed image of an invadopodial structure from RsK4 sarcoma cells on dermis-based matrix, showing thin F-actin fibers (green) capped with phosphotyrosine signal (red). Middle: a polarised rat embryo hippocampal neuron after three days in culture, expressing cytoplasmic green fluorescent protein (green) and immunolabeled for neuron-specific beta-III-tubulin (red), which marks the axon. Arrow – cell body with dendrites, arrowhead – axon. Right: an in vitro cultured tobacco pollen tube labeled with fluorescent antibodies against a component of the Exocyst complex (red) and tubulin (green). The broad-spectrum signal in the pollen grain (located at the top) corresponds to autofluorescence. Tube length can reach several milimeters after a few hours in culture.