Rapid cellular translocation is related to close contacts formed between various cultured cells and their substrata

Interference-reflection microscopy combined with time-lapse cinemicrography was used to examine the relationship between cell-to-substratum contact patterns and the speeds of translocation for a variety of cell types. Rapid translocation of amphibian leukocytes (average speed=9.0 μ/min), amphibian epidermal cells (7 μm/min) and teleost epidermal cells (7μm/min) was found to correlate with patterns of broad grey close contacts. Similar contact patterns were found under freshly seeded (2h) chick heart fibroblasts (moving 1-3 μm/min), the rapidly advancing (1-5 μm/min) margin of spreading human WI-38 fibroblasts, and isolated MDCK canine epithelial cells (0.5-1.0 μm/min). Conversely, numerous dark streaks of focal contact were found associated with the slow rate of translocation displayed by older cultures (72 h) of chick fibroblasts (<0.1 μm/min), well-spread WI-38 cells (≤0.3 μm/min) and confluent MDCK cells (<0.01 μm/min). It is concluded that close contacts, but not focal contacts, are associated with rapid cellular translocation, and that the build-up of focal contacts is associated with reduced cellular translocation and maintenance of the spread cell shape.