Microtubules and motor proteins: Mechanically regulated self-organization in vivo

Abstract

Abstract. A key aspect of life is sexual reproduction, which requires concerted movement. For successful mixing of the genetic material, molecular motors move the nucleus back and forth inside the cell. How motors work together to produce these large-scale movements, however, remains a mystery. To answer this question, we studied nuclear movement in fission yeast, which is driven by motor proteins pulling on microtubules. We show that motor proteins dynamically redistribute from one part of the cell to the other, generating asymmetric patterns of motors and, consequently, of forces that generate movement. By combining quantitative live cell imaging and laser ablation with a theoretical model, we find that this dynamic motor redistribution occurs purely as a result of changes in the mechanical strain sensed by the motor proteins. Our work therefore demonstrates that spatio-temporal pattern formation within a cell can occur as a result of mechanical cues (Vogel et al., 2009), which differs from conventional molecular signaling, as well as from self-organization based on a combination of biochemical reactions and diffusion.

The novel microtubule-associated CAP-glycine protein Cgp1 governs growth, differentiation, and virulence of Cryptococcus neoformans

“…C. neoformans infection can be initiated by the inhalation of infectious basidiospores generated through bisexual differentiation between cells of opposite mating types [ 34–36 ]. During this developmental process, dynamic regulation of the cytoskeleton is likely to occur [ 37 , 38 ]. To examine the role of Cgp1 in the developmental process, we constructed the cgp1 Δ mutant in the MAT a serotype A C. neoformans var.…”

Self-Organization and Coherency in Biology and Medicine

“…Dynein motors, responding to load forces, cooperatively detach from the trailing microtubules. After redistributing via the cytoplasm, they attach along the leading microtubules, thereby generating the force asymmetry necessary for the oscillations [71]. These cooperative effects were formalized using the equation for microtubules dynamics with forces exerted by the attached motors.…”

“…Meiotic nuclear oscillations crucial for proper chromosome pairing and recombination in yeast cells [71] as well as cellular biochemical processes responsible for e.g. self-regulating gene networks and phosphorylationdephosphorylation signaling [189] were also widely discussed within the concept of dynamic self-organization in far from thermodynamic equilibrium systems with feedback.…”