The localization of PHRAGMOPLAST ORIENTING KINESIN1 at the division site depends on the microtubule-binding proteins TANGLED1 and AUXIN-INDUCED IN ROOT CULTURES9 in Arabidopsis

Abstract

Proper plant growth and development requires spatial coordination of cell divisions. Two unrelated microtubule-binding proteins, TANGLED1 (TAN1) and AUXIN-INDUCED IN ROOT CULTURES9 (AIR9), are together required for normal growth and division-plane orientation in Arabidopsis (Arabidopsis thaliana). The tan1 air9 double mutant has synthetic growth and division-plane orientation defects while single mutants lack obvious defects. Here we show that the division site–localized protein, PHRAGMOPLAST ORIENTING KINESIN1 (POK1), was aberrantly lost from the division site during metaphase and telophase in the tan1 air9 mutant. Since TAN1 and POK1 interact via the first 132 amino acids of TAN1 (TAN11-132), we assessed the localization and function of TAN11-132 in the tan1 air9 double mutant. TAN11-132 rescued tan1 air9 mutant phenotypes and localized to the division site during telophase. However, replacing six amino-acid residues within TAN11-132, which disrupted the POK1–TAN1 interaction in the yeast-two-hybrid system, caused loss of both rescue and division-site localization of TAN11-132 in the tan1 air9 mutant. Full-length TAN1 with the same alanine substitutions had defects in phragmoplast guidance and reduced TAN1 and POK1 localization at the division site but rescued most tan1 air9 mutant phenotypes. Together, these data suggest that TAN1 and AIR9 are required for POK1 localization, and yet unknown proteins may stabilize TAN1–POK1 interactions.

De NovoTANGLED1 Recruitment to Aberrant Cell Plate Fusion Sites in Maize

“…We found that accumulation of TAN1-YFP at de novo cell plate insertion sites is partially dependent on the myosin XI O1. We hypothesized that since TAN1 interacts with PHRAGMOPLAST ORIENTING KINESIN1 (POK1) and POK2 (Müller, Han and Smith, 2006; Rasmussen, Sun and Smith, 2011; Mills, Morris and Rasmussen, 2022), and related kinesin 12s interact with myosin XI motor proteins including O1 (Huang et al ., 2022; Nan, Liang, et al ., 2023), O1 might be necessary for TAN1-YFP accumulation. TAN1-YFP fluorescence intensity during telophase was reduced but not absent in both correctly oriented and de novo cell plate fusion sites in o1 compared to wild-type siblings (Figure 4A-B, p = 1.02e-12, One-way ANOVA followed by Tukey’s HSD).…”

De novo TANGLED1 recruitment from the phragmoplast to aberrant cell plate fusion sites in maize

“…Accumulation of TAN1–YFP at de novo cell plate insertion sites is partially dependent on O1. Given that TAN1 interacts with PHRAGMOPLAST ORIENTING KINESIN1 (POK1) and POK2 ( Müller et al, 2006 ; Rasmussen et al, 2011 ; Mills et al, 2022 ), and related kinesin 12s interact with myosin XI motor proteins ( Huang et al, 2022 preprint; Nan et al, 2023 ), we hypothesized that O1 might be necessary for TAN1–YFP accumulation. TAN1–YFP fluorescence intensity during telophase was reduced but not absent in both correctly oriented and de novo cell plate fusion sites in o1 mutants compared to wild-type siblings [ Fig.…”

Cortical microtubules contribute to division plane positioning during telophase in maize

“…POK1 and POK2, which are plus end-directed kinesin-12 motor proteins that localize to the division site ( Lipka et al 2014 ; Chugh et al 2018 ; Herrmann et al 2018 ), might stabilize cortical-telophase microtubules. Since POK1 and POK2 directly interact with TAN1 ( Müller et al 2006 ; Rasmussen et al 2011 ; Lipka et al 2014 ; Mills et al 2022 ), they might also function together with TAN1 at the division site to capture microtubules. POK1 and POK2 may capture cortical-telophase microtubules at the division site just behind their plus ends and then move toward the plus ends, effectively pushing the minus ends away from the division site.…”