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BP: Fachverband Biologische Physik

BP 36: Cytoskeletal Filaments I

BP 36.3: Vortrag

Donnerstag, 19. März 2020, 15:30–15:45, SCH A251

What it takes to become a MAP — •Hauke Drechsler¹, Yong Xu¹, Veikko F. Geyer¹, Yixin Zhang¹, and Stefan Diez^1,2 — ¹B CUBE - Center for Molecular Bioengineering, Technische Universität Dresden, 01307 Dresden, Germany — ²Cluster of Excellence Physics of Life, Technische Universität Dresden, 01062 Dresden, Germany

The microtubule-binding domains of microtubule-associated proteins (MAPs) are structurally divergent, but often depend on electrostatic interactions with the negatively charged microtubule surface - suggesting that a MAP may primarily be defined by the surface exposure of positive charges rather than by a certain structural fold. Consistently, positively charged artificial objects are able to bind to microtubules and to diffuse along their lattice. Natural MAPs, however, exhibit a more sophisticated functionality beyond lattice-diffusion. Hence, we asked whether basic electrostatic interactions also support advanced MAP functionality. To test this, we studied simple positively charged peptides for the occurrence of typical MAP-like behavior. We found that a multivalent peptide construct featuring four lysine-alanine heptarepeats (starPEG-(KA7)4) shows advanced, biologically relevant MAP-like behavior: starPEG-(KA7)4 binds microtubules in the low nanomolar range, diffuses along their lattice, and tracks depolymerizing microtubule ends. Further, it promotes microtubule nucleation and growth, mediates depolymerization coupled pulling at plus ends, and bundles microtubules without significantly interfering with other proteins on the microtubule. Our results show that positive charges and multivalency are sufficient to mimic advanced MAP-like behavior.