Loading…

The Human EMAP-like Protein-70 (ELP70) Is a Microtubule Destabilizer That Localizes to the Mitotic Apparatus

In this report, we show that the e chinoderm m icrotubule (MT)- a ssociated p rotein (EMAP) and related E MAP- l ike p roteins (ELPs) share a similar domain organization with a highly conserved h ydrophobic ELP (HELP) domain and a large tryptophan-aspartic acid (WD) repeat domain. To determine the f...

Full description

Saved in:
Bibliographic Details
Published in:The Journal of biological chemistry 2002-01, Vol.277 (2), p.1301-1309
Main Authors: Eichenmuller, Bernd, Everley, Patrick, Palange, Jean, Lepley, Denise, Suprenant, Kathy A
Format: Article
Language:English
Subjects:
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:In this report, we show that the e chinoderm m icrotubule (MT)- a ssociated p rotein (EMAP) and related E MAP- l ike p roteins (ELPs) share a similar domain organization with a highly conserved h ydrophobic ELP (HELP) domain and a large tryptophan-aspartic acid (WD) repeat domain. To determine the function of mammalian ELPs, we generated antibodies against a 70-kDa human ELP and showed that ELP70 coassembled with MTs in HeLa cell extracts and colocalized with MTs in the mitotic apparatus. To determine whether ELP70 bound to MTs directly, human ELP70 was expressed and purified to homogeneity from baculovirus-infected Sf9 cells. Purified ELP70 bound to purified MTs with a stoichiometry of 0.40 ± 0.04 mol of ELP70/mol of tubulin dimer and with an intrinsic dissociation constant of 0.44 ± 0.13 μ m . Using a nucleated assembly assay and video-enhanced differential interference contrast microscopy, we demonstrated that ELP70 reduced seeded nucleation, reduced the growth rate, and promoted MT catastrophes in a concentration-dependent manner. As a result, ELP70-containing MTs were significantly shorter than MTs assembled from tubulin alone. These data indicate that ELP70 is a novel MT destabilizer. A lateral destabilization model is presented to describe ELP70's effects on microtubules.
ISSN:0021-9258
1083-351X
DOI:10.1074/jbc.M106628200