A calmodulin-sensitive interaction between microtubules and a higher plant homolog of elongation factor-1 alpha.

AUTOR(ES)

Durso, N A

RESUMO

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 Ca(2+)-dependent binding to calmodulin (CaM). This polypeptide was identified as a homolog of elongation factor-1 alpha (EF-1 alpha)--a highly conserved and ubiquitous protein translation factor. The carrot EF-1 alpha 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-1 alpha 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-1 alpha homolog mediates the lateral association of MTs in plant cells by a Ca2+/CaM-sensitive mechanism.

Documentos Relacionados

• A higher plant extracellular vitronectin-like adhesion protein is related to the translational elongation factor-1 alpha.
• Mechanisms of bacterial pathogenicity that involve production of calmodulin-sensitive adenylate cyclases.
• Secretion of cyclolysin, the calmodulin-sensitive adenylate cyclase-haemolysin bifunctional protein of Bordetella pertussis.
• Substrate proteins for calmodulin-sensitive and phospholipid-sensitive Ca2+-dependent protein kinases in heart, and inhibition of their phosphorylation by palmitoylcarnitine.
• Nucleotide sequence of rat elongation factor-1 alpha cDNA.