Search Results (6)

Low temperature affects rice growth and yield. Receptor-like protein kinases play an important role in plant growth and development. In order to reveal the role of a leucine-rich receptor like kinase LRK2 in low temperature stress and growth and development of rice. In this study, we used the obtained LRK2 overexpressing plants for experiments and the results show that the cold tolerance and yield of LRK2 overexpressing plants were higher than that of wild type. LRK2 has high homology with the phytosulfokine receptors (PSKRs) gene of different species, and LRK2 gene is responsive to phytosulfokine (PSK). In addition, we observed that the proline content of LRK2 overexpressing plants was significantly higher than that of the wild-type at low temperature, while the malondialdehyde content was significantly lower than that of the wild-type. Yeast two-hybrid screening and bimolecular fluorescence complementary analysis showed that LRK2 interacts with rice growth hormone response factor 24 (OsARF24) in vitro. These results suggest that LRK2 gene may be involved in the regulation of cold stress response and yield in rice. These findings will help us understand PSKR signaling in other grasses and support improvements in rice genetics. Full article

Background/Objectives: The phytosulfokine receptor (PSKR) gene family plays a crucial role in regulating plant growth, development, and stress response. Here, the PSKR gene family was characterized in Triticum aestivum L. The study aimed to bridge knowledge gaps and clarify the functional roles of TaPSKRs to create a solid foundation for examining the structure, functions, and regulatory aspects. Methods: The investigation involved genome-wide identification of PSKRs through collection and chromosomal assignment, followed by phylogenetic analysis and gene expression profiling. Additionally, interactions with their interactors were stimulated and analyzed to elucidate their function. Results: The wide-genome inspection of all TaPSKRs led to 25 genes with various homeologs, resulting in 57 TaPSKR members distributed among the A, B, and D subgenomes. Investigating the expression of 61 TaPSKR cDNAs in RNA-seq datasets generated from different growth stages at 14, 21, and 60 days old and diverse tissues such as leaves, shoots, and roots provided further insight into their functional purposes. The expression profile of the TaPSKRs resulted in three key clusters. Gene cluster 1 (GC 1) is partially associated with root growth, suggesting that specific TaPSKRs control root development. The GC 2 cluster targeted genes that show high levels of expression in all tested leaf growth stages and the early developmental stage of the shoots and roots. Furthermore, the GC 3 cluster was composed of genes that are constantly expressed, highlighting their crucial role in regulating various processes during the entire life cycle of wheat. Molecular docking simulations showed that phytosulfokine type α (PSK-α) interacted with all TaPSKRs and had a strong binding affinity with certain TaPSKR proteins, encompassing TaPSKR1A, TaPSKR3B, and TaPSKR13A, that support their involvement in PSK signaling pathways. The crucial arbitration of the affinity may depend on interactions between wheat PSK-α and PSKRs, especially in the LRR domain region. Conclusions: These discoveries deepened our knowledge of the role of the TaPSKR gene family in wheat growth and development, opening up possibilities for further studies to enhance wheat durability and yield via focused innovation approaches. Full article

Increasing numbers of reports have revealed novel catalytically active cryptic guanylate cyclases (GCs) and adenylate cyclases (ACs) operating within complex proteins in prokaryotes and eukaryotes. Here we review the structural and functional aspects of some of these cyclases and provide examples that illustrate their roles in the regulation of the intramolecular functions of complex proteins, such as the phytosulfokine receptor (PSKR), and reassess their contribution to signal generation and tuning. Another multidomain protein, Arabidopsis thaliana K⁺ uptake permease (AtKUP5), also harbors multiple catalytically active sites including an N-terminal AC and C-terminal phosphodiesterase (PDE) with an abscisic acid-binding site. We argue that this architecture may enable the fine-tuning and/or sensing of K⁺ flux and integrate hormone responses to cAMP homeostasis. We also discuss how searches with motifs based on conserved amino acids in catalytic centers led to the discovery of GCs and ACs and propose how this approach can be applied to discover hitherto masked active sites in bacterial, fungal, and animal proteomes. Finally, we show that motif searches are a promising approach to discover ancient biological functions such as hormone or gas binding. Full article

Phytosulfokine (PSK) is a disulfated pentapeptide that acts as a growth regulator to control plant growth and development as well as adaptability to biotic and abiotic stress. In the last three decades, PSK has drawn increasing attention due to its various functions. Preproproteins that have been tyrosine sulfonylated and then cleaved by specific enzymes contribute to mature PSK. To transfer a signal from the apoplast to the inner cells, the PSK peptide must bind to the PSK receptors (PSKR1 and PSKR2) at the cell surface. The precise mechanism of PSK signal transduction is still unknown, given that PSKR combines receptor and kinase activity with a capacity to bind calmodulin (CaM). The binding of PSK and PSKR stimulates an abundance of cGMP downstream from PSKR, further activating a cation-translocating unit composed of cyclic nucleotide-gated channel 17 (CNGC17), H⁺-ATPases AHA1 and AHA2, and BRI-associated receptor kinase 1 (BAK1). Recently, it has been revealed that posttranslational ubiquitination is closely related to the control of PSK and PSKR binding. To date, the majority of studies related to PSK have used Arabidopsis. Given that rapeseed and Arabidopsis share a close genetic relationship, the relevant knowledge obtained from Arabidopsis can be further applied to rapeseed. Full article

Phytosulfokine (PSK) is a phytohormone responsible for cell-to-cell communication in plants, playing a pivotal role in plant development and growth. The binding of PSK to its cognate receptor, PSKR1, is modulated by the formation of a binding site located between a leucine-rich repeat (LRR) domain of PSKR1 and the loop located in the receptor’s island domain (ID). The atomic resolution structure of the extracellular PSKR1 bound to PSK has been reported, however, the intrinsic dynamics of PSK binding and the architecture of the PSKR1 binding site remain to be understood. In this work, we used atomistic molecular dynamics (MD) simulations and free energy calculations to elucidate how the PSKR1 island domain (ID) loop forms and binds PSK. Moreover, we report a novel “druggable” binding site which could be exploited for the targeted modulation of the PSKR1-PSK binding by small molecules. We expect that our results will open new ways to modulate the PSK signalling cascade via small molecules, which can result in new crop control and agricultural applications. Full article

Plants as sessile organisms face daily environmental challenges and have developed highly nuanced signaling systems to enable suitable growth, development, defense, or stalling responses. Moonlighting proteins have multiple tasks and contribute to cellular signaling cascades where they produce additional variables adding to the complexity or fuzziness of biological systems. Here we examine roles of moonlighting kinases that also generate 3′,5′-cyclic guanosine monophosphate (cGMP) in plants. These proteins include receptor like kinases and lipid kinases. Their guanylate cyclase activity potentiates the development of localized cGMP-enriched nanodomains or niches surrounding the kinase and its interactome. These nanodomains contribute to allosteric regulation of kinase and other molecules in the immediate complex directly or indirectly modulating signal cascades. Effects include downregulation of kinase activity, modulation of other members of the protein complexes such as cyclic nucleotide gated channels and potential triggering of cGMP-dependent degradation cascades terminating signaling. The additional layers of information provided by the moonlighting kinases are discussed in terms of how they may be used to provide a layer of fuzziness to effectively modulate cellular signaling cascades. Full article