AGC1.5 Kinase Phosphorylates RopGEFs to Control Pollen Tube Growth

Li, En; Cui, Yong; Ge, Fu-Rong; Chai, Sen; Zhang, Yan; Feng, Qiang-Nan; Jiang, Liwen; Li, Sha

doi:10.1016/j.molp.2018.07.004

Cited by 49 publications

(65 citation statements)

References 61 publications

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“…It was suggested that the apical location of ROP1 in turn feed-forward regulates exocytosis of RLK and RopGEFs [5]. Another study reported that the phosphorylation of the PRONE domain of RopGEFs by AGC kinase was critical for the localization of RopGEFs to the apical PM, and subsequently for ROP activation and pollen tube polarity [47]. Cellular ROP signaling is also involved in root hair formation, another polar tip-growing plant cell type.…”

Section: Discussionmentioning

confidence: 99%

Genome-wide analysis of RopGEF gene family to identify genes contributing to pollen tube growth in rice (Oryza sativa)

et al. 2020

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Background: In plants, the key roles played by RopGEF-mediated ROP signaling in diverse processes, including polar tip growth, have been identified. Despite their important roles in reproduction, a comprehensive analysis of RopGEF members has not yet been performed in rice (Oryza sativa). To determine whether RopGEF regulators are involved in rice pollen tube growth, we performed genome-wide analysis of this family in rice. Results: Phylogenomic and meta-expression analysis of eleven RopGEFs in rice showed that four genes were preferentially expressed in mature pollen. These four genes contain the plant-specific Rop nucleotide exchanger (PRONE) domain and possible phosphorylated residues, suggesting a conserved role in polar tip growth with Arabidopsis thaliana. In subcellular localization analysis of the four RopGEFs through tobacco (Nicotiana benthamiana) infiltration, four proteins were predominantly identified in plasma membrane. Moreover, double mutants of RopGEF2/8 exhibited reduced pollen germination, causing partial male sterility. These genes possess unique cis-acting elements in their promoters compared with the other RopGEF genes. Conclusions: In this study, four RopGEF genes were identified as pollen-specific gene in eleven members of rice, and the expression pattern, promoter analysis, and evolutionary relationship of the RopGEF family were studied compared with Arabidopsis. Our study indicated that four RopGEF genes might function during pollen germination in distinct subcellular localization. Our study could provide valuable information on the functional study of RopGEF in rice.

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Section: Discussionmentioning

confidence: 99%

Genome-wide analysis of RopGEF gene family to identify genes contributing to pollen tube growth in rice (Oryza sativa)

et al. 2020

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“…arenosa [26,28,30]. AGC1.5 affects pollen tube growth by controlling ROP targeting by phosphorylating RopGEF proteins [115]. In Co. officinalis, a RopGEF protein is differentiated between ploidies [29].…”

Section: (C) Pollen Tube Tip Growthmentioning

confidence: 99%

When everything changes at once: finding a new normal after genome duplication

2020

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Whole-genome duplication (WGD), which leads to polyploidy, is implicated in adaptation and speciation. But what are the immediate effects of WGD and how do newly polyploid lineages adapt to them? With many studies of new and evolved polyploids now available, along with studies of genes under selection in polyploids, we are in an increasingly good position to understand how polyploidy generates novelty. Here, I will review consistent effects of WGD on the biology of plants, such as an increase in cell size, increased stress tolerance and more. I will discuss how a change in something as fundamental as cell size can challenge the function of some cell types in particular. I will also discuss what we have learned about the short- to medium-term evolutionary response to WGD. It is now clear that some of this evolutionary response may ‘lock in’ traits that happen to be beneficial, while in other cases, it might be more of an ‘emergency response’ to work around physiological changes that are either deleterious, or cannot be undone in the polyploid context. Yet, other traits may return rapidly to a diploid-like state. Polyploids may, by re-jigging many inter-related processes, find a new, conditionally adaptive, normal.

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“…We also identified PRK3, a protein receptor kinase, which is involved in ROP1 signaling activation and interacted with GEF members in Arabidopsis pollen tubes [ 8 ]. Two functionally redundant cytoplasmic kinases, AGC1.5 and AGC1.7, were also identified and these are reportedly involved in ROPGEFs phosphorylation to maintain the polar localization of ROP-GTP in apical PM [ 17 ]. Three RICs (for Rop-interactive CRIB motif-containing proteins) were identified as ROP1-associated proteins in our screen [ 24 , 32 ].…”

Section: Resultsmentioning

confidence: 99%

“…GTP-bound active form of Rho GTPase plays a pivotal role in various cellular processes via its interaction with a range of downstream effectors. The regulatory mechanism of Rho GTPase mediated by canonical GEF, GAP, and GDI is conserved across species, and these upstream regulators are often reported to result in GDP–GTP exchange of Rho GTPase, for example, the phosphorylation of RhoGEF members by PRK2 or AGC1.5 was demonstrated to lead to ROP1 activation in Arabidopsis pollen tube [ 16 , 17 ]. Hence, the dynamic balance of phosphorylation among GEF, GAP, and GDI plays a pivotal role for ROP1 signaling.…”

Section: Discussionmentioning

confidence: 99%

“…Major advances from pollen tube studies also indicated that the Rho small GTPase, ROP1, acts as a molecular switch that can be directly turned on/off by the conserved GTPase regulatory proteins RhoGEFs (guanine nucleotide exchange factors) and RhoGAPs (GTPase-activating protein) in Arabidopsis [ 14 ]. The autoinhibition release of RhoGEFs is required for the conversion of the Rho GTPase from the GDP-bound inactive form into an GTP-bound active form via an interaction with kinase family members [ 8 , 15 , 16 ], with RhoGEFs polar distribution in pollen tube being maintained by the cytoplasmic kinases AGC1.5/AGC1.7 [ 17 ]. The RhoGAP REN1 localizes to the apical plasma membrane (PM) region for the downstream regulation of ROP1 activity via ROP1-dependent vesicular exocytosis [ 18 ].…”

Section: Introductionmentioning

confidence: 99%

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Rho GTPase ROP1 Interactome Analysis Reveals Novel ROP1-Associated Pathways for Pollen Tube Polar Growth in Arabidopsis

Pang

et al. 2020

IJMS

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ROP (Rho-like GTPases from plants) GTPases are polarly localized key regulators of polar growth in pollen tubes and other cells in plants. However, how ROP GTPases are regulated and how they control polar growth remains to be fully understood. To gain new insights into ROP-dependent mechanisms underlying polar cell growth, we characterized the interactome of ROP1 GTPase that controls Arabidopsis pollen tube (PT) tip growth, an extreme form of polar cell growth. We established an efficient method for culturing Arabidopsis pollen tubes in liquid medium, which was used for immunoprecipitation/mass spectrometry-based identification of ROP1-associated proteins. A total of 654 candidates were isolated from the ROP1 interactome in Arabidopsis pollen tubes, and GO (Gene Ontology) classification and pathway analysis revealed multiple uncharacterized ROP1-dependent processes including translation, cell wall modification, post transcriptional modification, and ion homeostasis, in addition to known ROP1-dependent pathways. The ROP1-interactome data was further supported by the co-expression of the candidate interactors in highly mature pollen with PT germination and growth defects being discovered in 25% (8/32) of the candidate mutant genes. Taken together, our work uncovers valuable information for the identification and functional elucidation of ROP-associated proteins in the regulation of polar growth, and provides a reliable reference to identify critical regulators of polar cell growth in the future.

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AGC1.5 Kinase Phosphorylates RopGEFs to Control Pollen Tube Growth

Cited by 49 publications

References 61 publications

Genome-wide analysis of RopGEF gene family to identify genes contributing to pollen tube growth in rice (Oryza sativa)

Genome-wide analysis of RopGEF gene family to identify genes contributing to pollen tube growth in rice (Oryza sativa)

When everything changes at once: finding a new normal after genome duplication

Rho GTPase ROP1 Interactome Analysis Reveals Novel ROP1-Associated Pathways for Pollen Tube Polar Growth in Arabidopsis

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