Abstract
A group of microtubule-associated proteins called plus-end tracking proteins (+Tips), including End-Binding1 (EB1) family proteins, associates specifically with growing MT plus-ends. +Tips regulation plus-end dynamics and spatial arrangement, directly or indirectly.
Arabidopsis EB1 (AtEB1) tagged with GFP, decorated microtubule plus-ends, in transgenic Arabidopsis plants and in tobacco BY-2 cells. AtEB1 proteins share a conserved calponin homology (CH) domain at the N-terminus, an α-helical C-terminal domain, and a highly polar acidic tail with other homologues. EB1 proteins are thought to stabilize microtubule by forming a plus-end complex in yeast and metazoans, but plant EB1-containg complex is not characterized. When the CH-domain was deleted, the truncated AtEB1 formed a homo-dimer and lost the MT-binding capability. Removal of the acidic tail from EB1 activated microtubule assembly. We propose that AtEB1 takes an autoinhibitory conformation, as seen in animal EB1. We also report our attempt to identify EB1-interacting proteins using LC/MS/MS analysis approach.
