text: Human white blood cells use molecular paddles to swim Bizsiziz
  16 September 2020 bizsiziz
  Cells have evolved different strategies to migrate and explore their environment. For example, sperm cells, microalgae, and bacteria can swim through shape deformations or by using a whip-like appendage called a flagellum. By contrast, somatic mammalian cells are known to migrate by attaching to surfaces and crawling. It is widely accepted that leukocytes cannot migrate on 2-D surfaces without adhering to them.
  In contrast to previous studies, Theodoly, co-senior study author Chaouqi Misbah of Grenoble Alpes University, and their collaborators provide experimental and computational evidence in the new study that human leukocytes can migrate on 2-D surfaces without sticking to them and can swim using a mechanism that does not rely on changes in cell shape. "Looking at cell motion gives the illusion that cells deform their body like a swimmer," Misbah says. "Although leukocytes display highly dynamic shapes and seem to swim with a breast-stroke mode, our quantitative analysis suggests that these movements are inefficient to propel cells."
  Instead, the cells paddle using transmembrane proteins, which span the cell membrane and protrude outside the cell. The researchers show that membrane treadmilling—rearward movement of the cell surface—propels leukocyte migration in solid or liquid environments, with and without adhesion.
  Source:More information: Laurene Aoun et al, Amoeboid Swimming Is Propelled by Molecular Paddling in Lymphocytes, Biophysical Journal (2020). DOI: 10.1016/j.bpj.2020.07.033