ArabidopsisTONNEAU1 Proteins Are Essential for Preprophase Band Formation and Interact with Centrin

Abstract

Plant cells have specific microtubule structures involved in cell division and elongation. The tonneau1 (ton1) mutant of Arabidopsis thaliana displays drastic defects in morphogenesis, positioning of division planes, and cellular organization. These are primarily caused by dysfunction of the cortical cytoskeleton and absence of the preprophase band of microtubules. Characterization of the ton1 insertional mutant reveals complex chromosomal rearrangements leading to simultaneous disruption of two highly similar genes in tandem, TON1a and TON1b. TON1 proteins are conserved in land plants and share sequence motifs with human centrosomal proteins. The TON1 protein associates with soluble and microsomal fractions of Arabidopsis cells, and a green fluorescent protein-TON1 fusion labels cortical cytoskeletal structures, including the preprophase band and the interphase cortical array. A yeast two-hybrid screen identified Arabidopsis centrin as a potential TON1 partner. This interaction was confirmed both in vitro and in plant cells. The similarity of TON1 with centrosomal proteins and its interaction with centrin, another key component of microtubule organizing centers, suggests that functions involved in the organization of microtubule arrays by the centrosome were conserved across the evolutionary divergence between plants and animals.

TONNEAU2/FASS Regulates the Geometry of Microtubule Nucleation and Cortical Array Organization in Interphase Arabidopsis Cells

“…This interval contains a tandem duplication of homologous genes TON1A and TON1B, which were shown previously to be required for PPB formation (Azimzadeh et al, 2008). A mutation disrupting both the TON1A and TON1B genes resulted in a severe cell division phenotype similar to ton2 (Azimzadeh et al, 2008).…”

Eukaryotic Flagella: Variations in Form, Function, and Composition during Evolution

“…It suggests further flagellum-associated proteins may await discovery in land plants that do not build flagella. TONNEAU1 is required for normal cell morphogenesis: it orchestrates organization of the cortical microtubule cytoskeleton, interacts with the classic MTOC protein centrin, and has most recently been detected in a protein complex containing TONNEAU2 (Azimzadeh et al 2008, Spinner et al 2010, Spinner et al 2013. In other work, a screen for TONNEAU1-interacting proteins identified a novel family of 34 proteins that share in common six short sequence motifs; conservation of some of these motifs, including their order of appearance, is evident in another animal centrosomal protein, CEP350 (Drevensek et al 2012).…”

DWA1 and DWA2, Two Arabidopsis DWD Protein Components of CUL4-Based E3 Ligases, Act Together as Negative Regulators in ABA Signal Transduction

“…The entire open reading frames (from start codon to stop codon) of DWA1 and DWA2 were cloned via Gateway reactions into the binary pBiFC vectors (Azimzadeh et al, 2008) containing either N-or C-terminal yellow fluorescent protein (YFP) fragments (YFP N and YFP C ). The primers used (DWA1_BiFc_F, DWA1_BiFc_R, DWA2_BiFc_F, and DWA2_BiFc_R) are shown in Supplemental Table 3 online.…”