Ethylene and programmed cell death in plants

Botany ◽  
2009 ◽  
Vol 87 (8) ◽  
pp. 757-769 ◽  
Author(s):  
Christopher P. Trobacher
Keyword(s):  
Signal Transduction ◽  
Cell Death ◽  
Programmed Cell Death ◽  
Adventitious Roots ◽  
Future Research ◽  
Aerenchyma Formation ◽  
Gaseous Hydrocarbon ◽  
Reproductive Structures ◽  
Ethylene Signalling ◽  
Ethylene Signal

Plants produce and utilize the gaseous hydrocarbon ethylene as a phytohormone throughout their life cycle. Ethylene is notoriously associated with fruit ripening and this aspect of its biology, along with its biosynthesis and mechanisms of signal transduction, has received a great deal of study. Many plants also employ ethylene signalling during instances of programmed cell death (PCD), including aerenchyma formation, epidermal PCD above emerging adventitious roots, senescence of petals, leaves, and reproductive structures, and endosperm death in developing cereal seeds. Ethylene-signalling during PCD is both spatially and temporally regulated, and is selective in that it induces PCD only in sensitized cells or tissues. This review examines instances of ethylene-regulated plant PCD, proposes a general model, and suggests avenues for future research that might improve our understanding of both PCD and ethylene signal transduction.

scholarly journals Calcium Signaling in Plant Programmed Cell Death

Cells ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1089
Author(s):  
Huimin Ren ◽  
Xiaohong Zhao ◽  
Wenjie Li ◽  
Jamshaid Hussain ◽  
Guoning Qi ◽  
...  
Keyword(s):  
Cell Death ◽  
Programmed Cell Death ◽  
Abiotic Stresses ◽  
Animal Studies ◽  
Future Research ◽  
Significant Progress ◽  
Biotic And Abiotic Stresses ◽  
Stress Perception ◽  
The Past

Programmed cell death (PCD) is a process intended for the maintenance of cellular homeostasis by eliminating old, damaged, or unwanted cells. In plants, PCD takes place during developmental processes and in response to biotic and abiotic stresses. In contrast to the field of animal studies, PCD is not well understood in plants. Calcium (Ca2+) is a universal cell signaling entity and regulates numerous physiological activities across all the kingdoms of life. The cytosolic increase in Ca2+ is a prerequisite for the induction of PCD in plants. Although over the past years, we have witnessed significant progress in understanding the role of Ca2+ in the regulation of PCD, it is still unclear how the upstream stress perception leads to the Ca2+ elevation and how the signal is further propagated to result in the onset of PCD. In this review article, we discuss recent advancements in the field, and compare the role of Ca2+ signaling in PCD in biotic and abiotic stresses. Moreover, we discuss the upstream and downstream components of Ca2+ signaling and its crosstalk with other signaling pathways in PCD. The review is expected to provide new insights into the role of Ca2+ signaling in PCD and to identify gaps for future research efforts.

Efficacy of PD-1 or PD-L1 inhibitors and central nervous system metastases in advanced cancer: a meta-analysis

2021 ◽  
Vol 21 ◽  
Author(s):  
Minyong Peng ◽  
Shan Li ◽  
Hui Xiang ◽  
Wen Huang ◽  
Weiling Mao ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Overall Survival ◽  
Cell Death ◽  
Nervous System ◽  
Programmed Cell Death ◽  
Future Research ◽  
Significant Heterogeneity ◽  
Cns Metastases ◽  
Hazard Ratios ◽  
Significant Difference

<P>Background: Little is known about the efficacy of programmed cell death protein-1 (PD-1) or programmed cell death-ligand 1 (PD-L1) inhibitors in patients with central nervous system (CNS) metastases. <P> Objective: Assess the difference in efficacy of PD-1 or PD-L1 inhibitors in patients with and without CNS metastases. <P> Methods: From inception to March 2020, PubMed and Embase were searched for randomized controlled trials (RCTs) about PD-1 or PD-L1 inhibitors. Only trails with available hazard ratios (HRs) for overall survival (OS) of patients with and without CNS metastases simultaneously would be included. Overall survival hazard ratios and their 95% confidence interval (CI) were calculated, and the efficacy difference between these two groups was assessed in the meantime. <P> Results: 4988 patients (559 patients with CNS metastases and 4429 patients without CNS metastases) from 8 RCTs were included. In patients with CNS metastases, the pooled HR was 0.76 (95%CI, 0.62 to 0.93), while in patients without CNS metastases, the pooled HR was 0.74 (95%CI, 0.68 to 0.79). There was no significant difference in efficacy between these two groups (Χ=0.06 P=0.80). <P> Conclusion: With no significant heterogeneity observed between patients with or without CNS metastases, patients with CNS metastases should not be excluded from PD-1 or PD-L1 blockade therapy. Future research should permit more patients with CNS metastases to engage in PD-1 or PD-L1 blockade therapy and explore the safety of PD-1 or PD-L1 inhibitors in patients with CNS metastases.</P>

scholarly journals Death-associated protein kinase (DAPK) and signal transduction: blebbing in programmed cell death

FEBS Journal ◽  
2009 ◽  
Vol 277 (1) ◽  
pp. 58-65 ◽  
Author(s):  
Miia Bovellan ◽  
Marco Fritzsche ◽  
Craig Stevens ◽  
Guillaume Charras
Keyword(s):  
Signal Transduction ◽  
Cell Death ◽  
Protein Kinase ◽  
Programmed Cell Death ◽  
Death Associated Protein Kinase

scholarly journals Programmed Cell Death and Aerenchyma Formation in Water-Logged Sunflower Stems and Its Promotion by Ethylene and ROS

2019 ◽  
Vol 9 ◽  
Author(s):  
Xi-Lu Ni ◽  
Meng-Yuan Gui ◽  
Ling-Ling Tan ◽  
Qiang Zhu ◽  
Wen-Zhe Liu ◽  
...  
Keyword(s):  
Cell Death ◽  
Programmed Cell Death ◽  
Aerenchyma Formation

scholarly journals Molecular dynamics of the immune checkpoint programmed cell death protein I, PD-1: conformational changes of the BC-loop upon binding of the ligand PD-L1 and the monoclonal antibody nivolumab

2020 ◽  
Vol 21 (S17) ◽  
Author(s):  
Bernhard Roither ◽  
Chris Oostenbrink ◽  
Wolfgang Schreiner
Keyword(s):  
Molecular Dynamics ◽  
Signal Transduction ◽  
T Cells ◽  
Cell Death ◽  
Programmed Cell Death ◽  
Conformational Changes ◽  
Immune Checkpoint ◽  
Active Conformation ◽  
Dynamics Simulations ◽  
Cell Death Protein

Abstract Background The immune checkpoint receptor programmed cell death protein I (PD-1) has been identified as a key target in immunotherapy. PD-1 reduces the risk of autoimmunity by inducing apoptosis in antigen-specific T cells upon interaction with programmed cell death protein ligand I (PD-L1). Various cancer types overexpress PD-L1 to evade the immune system by inducing apoptosis in tumor-specific CD8+ T cells. The clinically used blocking antibody nivolumab binds to PD-1 and inhibits the immunosuppressive interaction with PD-L1. Even though PD-1 is already used as a drug target, the exact mechanism of the receptor is still a matter of debate. For instance, it is hypothesized that the signal transduction is based on an active conformation of PD-1. Results Here we present the results of the first molecular dynamics simulations of PD-1 with a complete extracellular domain with a focus on the role of the BC-loop of PD-1 upon binding PD-L1 or nivolumab. We could demonstrate that the BC-loop can form three conformations. Nivolumab binds to the BC-loop according to the conformational selection model whereas PD-L1 induces allosterically a conformational change of the BC-loop. Conclusion Due to the structural differences of the BC-loop, a signal transduction based on active conformation cannot be ruled out. These findings will have an impact on drug design and will help to refine immunotherapy blocking antibodies.

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