Novel Arabidopsis microtubule-associated proteins track growing microtubule plus ends

Jeh Haur Wong, Takashi Hashimoto

Research output: Contribution to journalArticlepeer-review

14 Scopus citations

Abstract

Background: Microtubules (MTs) are polarized polymers with highly dynamic plus ends that stochastically switch between growth and shrinkage phases. In eukaryotic cells, a plethora of MT-associated proteins (MAPs) regulate the dynamics and higher-order organization of MTs to mediate distinct cellular functions. Plus-end tracking proteins (+TIPs) are a group of MAPs that specifically accumulate at the growing MT plus ends, where they modulate the behavior of the MT plus ends and mediate interactions with cellular targets. Although several functionally important + TIP proteins have been characterized in yeast and animals, little is known about this group of proteins in plants. Results: We report here that two homologous MAPs from Arabidopsis thaliana, Growing Plus-end Tracking 1 (GPT1) and GPT2 (henceforth GPT1/2), contain basic MT-binding regions at their central and C-terminal regions, and bind directly to MTs in vitro. Interestingly, GPT1/2 preferentially accumulated at the growing plus ends of cortical MTs in interphase Arabidopsis cells. When the GPT1/12-decorated growing plus ends switched to rapid depolymerization, GPT1/2 dissociated from the MT plus ends. Conversely, when the depolymerizing ends were rescued and started to polymerize again, GPT1/2 were immediately recruited to the growing MT tips. This tip tracking behavior of GPT proteins does not depend on the two established plant + TIPs, End-Binding protein 1 (EB1) and SPIRAL1 (SPR1). Conclusions: The Arabidopsis MAPs GPT1 and GPT2 bind MTs directly through their basic regions. These MAPs track the plus ends of growing MTs independently of EB1 and SPR1 and represent a novel plant-specific + TIP family.

Original languageEnglish (US)
Article number33
JournalBMC plant biology
Volume17
Issue number1
DOIs
StatePublished - Feb 2 2017

Bibliographical note

Funding Information:
This work was supported by a Grant-in-Aid for Scientific Research on Innovative Areas from the Ministry of Education, Culture, Sports, Science, and Technology (grant no. 24114004 to T.H.). The funder had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Publisher Copyright:
© 2017 The Author(s).

Keywords

  • Arabidopsis
  • EB1
  • GPT1
  • GPT2
  • Plus-end tracking proteins
  • SPIRAL1

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