Neil A. Durso and Richard J. Cyr
|
A Calmodulin-sensitive Interaction between Microtubules and a Higher Plant Homolog of Elongation Factor-1-alpha |
![]()
© 1994 American Society of Plant Physiologists |
Abstract
The microtubules (MTs) of higher plant cells are organized into
arrays with essential functions in plant cell growth and differentiation;
however, molecular mechanisms underlying the organization and
regulation of these arrays remain largely unknown. We have approached
this problem using tubulin affinity chromatography to isolate
carrot proteins that interact with MTs. From these proteins,
a 50 kD polypeptide was selectively purified by exploiting its
Ca2+-dependent binding to calmodulin (CaM). This polypeptide
was identified as a homolog of elongation factor-1a (EF-1a)
a highly conserved and ubiquitous protein translation factor.
The carrot EF-1a homolog bundles MTs in vitro, and moreover,
this bundling is modulated by the addition of Ca2+
and CaM together -- Ca2+/CaM. A direct binding between
the EF-1a homolog and MTs was demonstrated, providing novel evidence
for such an interaction. Based on these findings, and others
discussed herein, we propose that an EF-1a homolog mediates the
lateral association of MTs in plant cells by a Ca2+/CaM-sensitive
mechanism. Keywords: Calcium; Calmodulin; Carrot cells; Elongation factor-1-alpha; Microtubule-associated protein. |
©1996 Neil A Durso, III Free host = GeoCities |
|