Taxis is a behavioral response of a cell or an organism to an external stimulus. The movement is characteristically directional. The movement may be positive or negative. A positive taxis is one in which the organism or a cell moves towards the source of stimulation (attraction). A negative taxis is when the organism or a cell moves away from the source of stimulation (repulsion).
There are many types of taxis identified and one of them is durotaxis. It is a form of cell movement wherein cells are guided by rigidity or stiffness gradient. For instance, a cell will move towards the direction of greater stiffness.1
The term was coined by Lo and colleagues in their paper published in 2000 where they presented their hypothesis that individual cells were capable of detecting substrate stiffness through active tactile exploration.2
Word origin: Latin dūrāre, dūrō, from Proto-Indo-European dewǝ- (“to run forward”) + taxis
1 Plotnikov, S. V., Pasapera, A. M., Sabass, B., and Waterman, C. M. (21 December 2012). "Force fluctuations within focal adhesions mediate ECM-rigidity sensing to guide directed cell migration." Cell 151 (7): 1513–27.
2 Lo, C. (1 July 2000). "Cell Movement Is Guided by the Rigidity of the Substrate". Biophysical Journal 79 (1): 144–152.