Click on any image for more information.
Lymphocytes circulating in the blood are normally spherical with randomly displayed microvilli.
When a lymphocyte is activated to migrate, it polarizes its organelles. The centrioles and an umbrella like array of microtubules and intermediate sized filaments appears to create cell rigidity that may stabilize shape or inhibit locomotion. As Ratner proposes, removal of microtubules to the uropod may release it from inhibition. Shin Young Park and Betsy Repasky of Roswell Park Cancer Institute find that Protein kinase C and Spectrin also go to the Uropod as lymphocytes begin to move. Cytoskeletal polarization seems to be aligned so that acquisition of signal and intitiation of movement are correctly at opposite ends of the cell.