Multivalent electrostatic microtubule interactions of synthetic peptides are sufficient to mimic advanced MAP-like behavior

Research output: Contribution to journalResearch articleContributedpeer-review

Abstract

Microtubule-associated proteins (MAPs) are a functionally highly diverse class of proteins that help to adjust the shape and function of the microtubule cytoskeleton in space and time. For this purpose, MAPs structurally support microtubules, modulate their dynamic instability, or regulate the activity of associated molecular motors. The microtubule-binding domains of MAPs are structurally divergent, but often depend on electrostatic interactions with the negatively charged surface of the microtubule. This suggests that the surface exposure of positive charges rather than a certain structural fold is sufficient for a protein to associate with microtubules. Consistently, positively charged artificial objects have been shown to associate with microtubules and to diffuse along their lattice. Natural MAPs, however, show a more sophisticated functionality beyond lattice-diffusion. Here, we asked whether basic electrostatic interactions are sufficient to also support advanced MAP functionality. To test this hypothesis, we studied simple positively charged peptide sequences for the occurrence of typical MAP-like behavior. We found that a multivalent peptide construct featuring four lysine-alanine heptarepeats (starPEG-(KA7)4)-but not its monovalent KA7-subunits-show advanced, biologically relevant MAP-like behavior: starPEG-(KA7)4 binds microtubules in the low nanomolar range, diffuses along their lattice with the ability to switch between intersecting microtubules, and tracks depolymerizing microtubule ends. Further, starPEG-(KA7)4 promotes microtubule nucleation and growth, mediates depolymerization coupled pulling at plus ends, and bundles microtubules without significantly interfering with other proteins on the microtubule lattice (as exemplified by the motor kinesin-1). Our results show that positive charges and multivalency are sufficient to mimic advanced MAP-like behavior.

Details

Original languageEnglish
Pages (from-to)2953-2968
Number of pages16
JournalMolecular Biology of the Cell
Volume30
Issue number24
Publication statusPublished - 15 Nov 2019
Peer-reviewedYes

External IDs

PubMedCentral PMC6857568
Scopus 85075090597
ORCID /0000-0002-0750-8515/work/142235552
ORCID /0000-0003-1884-2284/work/142242162
ORCID /0000-0002-6669-4995/work/142251854

Keywords

Research priority areas of TU Dresden

Keywords

  • Alanine/metabolism, Animals, Chemistry Techniques, Synthetic/methods, Cytoskeleton/metabolism, Diffusion, Humans, Kinesins/metabolism, Lysine/metabolism, Microtubule-Associated Proteins/metabolism, Microtubules/metabolism, Peptides/chemistry, Polymerization, Protein Binding/physiology, Static Electricity, Tubulin/metabolism

Library keywords