Characterization of TCTP, the translationally controlled tumor protein, from Arabidopsis thaliana

Date

2008

Authors

Berkowitz, Oliver
Jost, Ricarda
Pollmann, Stephan
Masle, Josette

Journal Title

Journal ISSN

Volume Title

Publisher

American Society of Plant Biologists

Abstract

The translationally controlled tumor protein (TCTP) is an important component of the TOR (target of rapamycin) signaling pathway, the major regulator of cell growth in animals and fungi. TCTP acts as the guanine nucleotide exchange factor of the Ras GTPase Rheb that controls TOR activity in Drosophila melanogaster. We therefore examined the role of Arabidopsis thaliana TCTP in planta. Plant TCTPs exhibit distinct sequence differences from nonplant homologs but share the key GTPase binding surface. Green fluorescent protein reporter lines show that Arabidopsis TCTP is expressed throughout plant tissues and developmental stages with increased expression in meristematic and expanding cells. Knockout of TCTP leads to a male gametophytic phenotype with normal pollen formation and germination but impaired pollen tube growth. Silencing of TCTP by RNA interference slows vegetative growth; leaf expansion is reduced because of smaller cell size, lateral root formation is reduced, and root hair development is impaired. Furthermore, these lines show decreased sensitivity to an exogenously applied auxin analog and have elevated levels of endogenous auxin. These results identify TCTP as an important regulator of growth in plants and imply a function of plant TCTP as a mediator of TOR activity similar to that known in nonplant systems.

Description

Keywords

Keywords: Arabidopsis protein; amino acid sequence; Arabidopsis; article; chemistry; gene expression profiling; genetics; growth, development and aging; immunoblotting; metabolism; molecular genetics; physiology; plant root; pollen; protein secondary structure; rev

Citation

Source

The Plant Cell

Type

Journal article

Book Title

Entity type

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Restricted until

2037-12-31