Biology subjects

Mang, H.

Publications and source records attributed to Mang, H..

5 recordsLinked to original sources

bioRxiv2023

BRCA1 and BRCA2 germline mutations driven signaling pathway alterations are sufficient to initiate breast tumorigenesis by the PIK3CAH1047R oncogene.

Single cell transcriptomics studies have begun to identify breast epithelial cell and stromal cell specific transcriptome differences between BRCA1/2 mutation carriers and non-carriers. We generated a single cell transcriptome atlas of breast tissues from BRCA1, BRCA2 mutation carriers and compared this single cell atlas of mutation carriers with our previously described single cell breast atlas of healthy non-carriers. We observed that BRCA1 but not BRCA2 mutations altered the ratio between basal, luminal progenitor and mature luminal cells in breast tissues. A unique subcluster of cells within luminal progenitors is underrepresented in case of BRCA1 and BRCA2 mutation carriers compared to non-carriers. Both BRCA1 and BRCA2 mutations specifically altered transcriptomes in epithelial cells which are an integral part of NF-{kappa}B, LARP1, and MYC signaling. Reduction of MYC signaling and translational machinery in BRCA1/2 mutant epithelial cells is reminiscent of embryonic diapause-like adaptation that occurs in drug tolerant populations of cells. Signaling pathway alterations in epithelial cells unique to BRCA1 mutations included STAT3, BRD4, SMARCA4, HIF2A/EPAS1, and Inhibin-A signaling. BRCA2 mutations were associated with upregulation of IL-6, PDK1, FOXO3, and TNFSF11 signaling. These signaling pathway alterations are sufficient to alter sensitivity of BRCA1/BRCA2-mutant breast epithelial cells to transformation as epithelial cells from BRCA1 mutation carriers overexpressing hTERT + PIK3CAH1047R generated adenocarcinomas, whereas similarly modified mutant BRCA2 cells generated basal carcinomas in NSG mice. Thus, our studies provide a high-resolution transcriptome atlas of breast epithelial cells of BRCA1 and BRCA2 mutation carriers and reveal their susceptibility to PIK3CA mutation-driven transformation. Statement of SignificanceThis study provides a single cell atlas of breast tissues of BRCA1/2 mutation carriers and demonstrates that aberrant signaling due to BRCA1/2 mutations sufficient to initiate breast cancer by mutant PIK3CA.

cancer biology↗

bioRxiv2022

Ptr1 and ZAR1 immune receptors confer overlapping and distinct bacterial pathogen effector specificities

Nucleotide-binding and leucine-rich repeat receptors (NLRs) detect pathogen effectors inside the plant cell. To identify Nicotiana benthamiana NLRs (NbNLRs) with novel effector recognition specificity, we designed an NbNLR VIGS library and conducted a rapid reverse genetic screen. During the NbNLR VIGS library screening, we identified that N. benthamiana homolog of Ptr1 (PSEUDOMONAS SYRINGAE PV. TOMATO RACE 1 RESISTANCE) recognizes the Pseudomonas effectors AvrRpt2, AvrRpm1, and AvrB. We demonstrated that recognition of the Xanthomonas effector AvrBsT and the Pseudomonas effector HopZ5 in N. benthamiana is conferred independently by N. benthamiana homolog of Ptr1 and ZAR1 (HOPZ-ACTIVATED RESISTANCE 1). In addition, we showed that the RLCK XII family protein JIM2 (XOPJ4 IMMUNITY 2) physically interacts with AvrBsT and HopZ5 and is required for the NbZAR1-dependent recognition of AvrBsT and HopZ5. The recognition of multiple bacterial effectors by Ptr1 and ZAR1 in N. benthamiana demonstrates a convergent evolution of effector recognition across plant species. Identification of key components involved in Ptr1 and ZAR1 mediated immunity would reveal unique mechanisms of expanded effector recognition and be useful for engineering resistance in solanaceous crops.

plant biology↗

bioRxiv2022

The Phytophthora capsici RxLR effector CRISIS2 has roles in suppression of PTI and triggering cell death in host plant

Pathogen effectors can suppress various plant immune responses, suggesting that they have multiple targets in the host. To understand the mechanisms underlying plasma membrane-associated and effector-mediated immunity, we performed Phytophthora capsici RxLR cell death Inducer Suppressing Immune System (CRISIS) screening. In Nicotiana benthamiana, the cell death induced by the RxLR effector CRISIS2 is inhibited by the irreversible plasma membrane H+-ATPase (PMA) activator fusicoccin. Biochemical and gene silencing analyses revealed that CRISIS2 physically and functionally associates with PMAs and induces host cell death independent of immune receptors. CRISIS2 induces apoplastic alkalization by suppressing PMA activity via its association with the C-terminal regulatory domain of PMA. In planta expression of CRISIS2 significantly enhanced the virulence of P. capsici, whereas host-induced gene silencing of CRISIS2 compromised disease symptom and biomass of P. capsici. Furthermore, co-immunoprecipitation assays revealed that CRISIS2 constitutively associates with BAK1, the co-receptor of pattern recognition receptors (PRRs). CRISIS2 interferes with the FLS2-BAK1 complex induced by flagellin perception and impairs downstream signaling from the PRR complex. Proteomics and gene silencing assays identified putative PRRs that negatively regulate the virulence of P. capsici in N. benthamiana as interactors of CRISIS2 and BAK1. Our study identified a novel RxLR effector playing multiple roles in the suppression of plant defense and induction of cell death to support the pathogen hemibiotrophic life cycle in the host plant.

plant biology↗

bioRxiv2020

Plant NLR targets P-type ATPase for executing plasma membrane depolarization leading to calcium influx and cell death

Hypersensitive response (HR) is a robust immune response mediated by plant nucleotide-binding and leucine-rich repeat receptor (NLR). However, the early molecular event linking NLR to cell death is obscure. Here we demonstrate that NLR targets plasma membrane H+-ATPases (PMA) generating electrochemical potential across the membrane. CCA309, an autoactive N-terminal domain of pepper coiled-coil NLR (CNL), associates with PMAs and its autoactivity is affected by silencing or overexpression of PMA. CCA309-induced extracellular alkalization accompanied with membrane depolarization is followed by calcium influx and cell death. CCA309 interacts with C-terminal regulatory domain of PMA and 14-3-3 negatively affects CCA309-induced cell death. Moreover, pharmacological experiments with fusicoccin, an irreversible PMA activator, confirmed that CC- and CNL-mediated cell death occurred through inhibiting PMA. We propose PMAs as the primary target of plasma membrane-associated CNL to disrupt electrochemical homeostasis leading to HR cell death.

plant biology↗

bioRxiv2019

Genome-wide expression analysis of immune receptors in hot pepper reveals an autonomous NLR cluster in higher plants

Plants possess hundreds of intracellular immune receptors encoding nucleotide-binding domain and leucine-rich repeat (NLR) proteins. Autoactive NLRs, in some cases a specific NLR domain, induce plant cell death in the absence of pathogen infection. In this study, we identified a group of NLRs (G10) carrying autoactive coiled-coil (CC) domains in pepper (Capsicum annuum L. cv. CM334) by genome-wide transient expression analysis. The G10-CC-mediated cell death mimics hypersensitive response (HR) cell death triggered by interaction between NLR and effectors derived from pathogens. Sequence alignment and mutagenesis analyses revealed that the intact 1 helix of G10-CCs is critical for both G10-CC- and R gene-mediated HR cell death. The cell death induced by G10-CCs does not require known helper NLRs, suggesting G10-NLRs are novel singleton NLRs. We also found that G10-CCs localize in the plasma membrane as Arabidopsis singleton NLR ZAR1. Extended studies revealed that autoactive G10-CCs are well conserved in other Solanaceae plants, including tomato, potato, and tobacco, as well as a monocot plant, rice. Furthermore, G10-NLR is an ancient form of NLR that present in all tested seed plants (spermatophytes). Our studies not only uncover the autonomous NLR cluster in plants but also provide powerful resources for dissecting the underlying molecular mechanism of NLR-mediated cell death in plants.

plant biology↗