How cortical waves drive fission of motile cells

Abstract

Cytokinesis—the division of a cell into two daughter cells—is a key step in cell growth and proliferation. It typically occurs in synchrony with the cell cycle to ensure that a complete copy of the genetic information is passed on to the next generation of daughter cells. In animal cells, cytokinesis commonly relies on an actomyosin contractile ring that drives equatorial furrowing and separation into the two daughter cells. However, also contractile ring-independent forms of cell division are known that depend on substrate-mediated traction forces. Here, we report evidence of an as yet unknown type of contractile ring-independent cytokinesis that we termed wave-mediated cytofission. It is driven by self-organized cortical actin waves that travel across the ventral membrane of oversized, multinucleatedDictyostelium discoideumcells. Upon collision with the cell border, waves may initiate the formation of protrusions that elongate and eventually pinch off to form separate daughter cells. They are composed of a stable elongated wave segment that is enclosed by a cell membrane and moves in a highly persistent fashion. We rationalize our observations based on a noisy excitable reaction–diffusion model in combination with a dynamic phase field to account for the cell shape and demonstrate that daughter cells emerging from wave-mediated cytofission exhibit a well-controlled size.

Non‐Equilibrium Large‐Scale Membrane Transformations Driven by MinDE Biochemical Reaction Cycles

“…Moreover,w ith lower concentration of DOPG or Mg 2+ , Min oscillations promoted robust bud formation from the planar flat vesicles.I nt he absence of other more complex bud-forming protein machineries,M in oscillations provided the non-equilibrium cue to support these continuous membrane transformations through mechano-chemical coupling. [27] Since the pancake shapes of our flat vesicle membranes are abundant in living cells,s uch as lamellipodia or pseudopods of moving cells [28] and flattened ER cisternae and Golgi, [29] this model membrane assay holds great promise to generally explore advanced protein functions [30] in the context of synthetic and artificial cells.…”

Micro-topographical guidance of macropinocytic signaling patches

“…6A, 600 ~ 750 sec). Despite large stretching, there was no cell division or fragmentation as observed in giant cells fused by electric pulses (Flemming et al, 2020). To gain an insight into the process of the ridge selection, the time evolution of patch size and cell elongation along the respective branch were analyzed (Fig.…”

Why a Large-Scale Mode Can Be Essential for Understanding Intracellular Actin Waves

“…IAW can also act as the force-generating element that directly drives the division process in a contractile ring-independent form of cytofission. This was observed in D. discoideum cells beyond a critical size, where waves that collide with the cell border not only induce strong deformations of the cell shape but also trigger the division into smaller daughter cells—a cell cycle-independent form of wave-mediated cytofission, see Figure 1 C [ 53 ]. Macropinocytosis While functional roles in phagocytosis and motility have been proposed [ 54 , 55 ], recent genetic studies suggest a relation to macropinocytosis [ 56 ].…”

“…( C ) Wave-mediated binary cytofission in a Dictyostelium discoideum cell, scale bar 10 m. An actin wave in a cell with two nuclei becomes unstable and splits into two independent segments that move in opposite directions and induce a cytofission event. Panels ( A ) and ( B ) are reproduced from [ 50 ] and panel ( C ) is reproduced from [ 53 ]. Copyright 2020 National Academy of Sciences.…”