Contact guidance refers to the ability of cells to sense the geometrical features of the microenvironment and respond by changing their shape and adopting the appropriate orientation. Inhibition and ablation of nonmuscle myosin 2 (NM2) paralogues have demonstrated their importance for contact guidance. However, the specific roles of the NM2 paralogues have not been systematically studied. In this work we use micropatterned substrates to examine the roles of NM2A and NM2B and to elucidate the relationship of the microenvironment, actomyosin, and microtubules in contact guidance. We show that contact guidance is preserved following loss of NM2B and that expression of NM2A alone is sufficient to establish an appropriate orientation of the cells. Loss of NM2B and overexpression of NM2A result in a prominent cell polarization that is found to be linked to the increased alignment of microtubules with the actomyosin scaffold. Suppression of actomyosin with blebbistatin reduces cell polarity on a flat surface, but not on a surface with contact guidance cues. This indicates that the lost microtubule–actomyosin interactions are compensated for by microtubule–mi-croenvironment interactions, which are sufficient to establish cell polarity through contact guidance.
Bibliographical noteFunding Information:
This work was enhanced by advice from Sachiyo Kawamoto and Mary Anne Conti (National Heart, Lung, and Blood Institute [NHLBI]); Tatyana Svitkina (University of Pennsylvania); Bridgette Heine, Kem A. Sochacki, and Justin W. Taraska (NHLBI); and Christian Combs and Daniela Malide (NHLBI). It was supported by the NHLBI Division of Intramural Research (HL006209), a Research Scholar Grant, RSG-14-171-01-CSM, from the American Cancer Society to P.P.P., and the National Institutes of Health (R01CA181385 and U54CA210190 University of Minnesota Physical Sciences in Oncology Center to P.P.P.).