scholarly journals Mdm2-Mediated Downmodulation of GRK2 Restricts Centrosome Separation for Proper Chromosome Congression

Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 729
Author(s):  
Clara Reglero ◽  
Belén Ortiz del Castillo ◽  
Verónica Rivas ◽  
Federico Mayor ◽  
Petronila Penela
Keyword(s):  
Hippo Pathway ◽  
Growth Factor Receptor ◽  
Receptor Kinase ◽  
Egfr Signaling ◽  
Polyubiquitin Chains ◽  
Centrosome Separation ◽  
Chromosome Congression ◽  
Epidermal Growth ◽  
The Hippo Pathway ◽  
G Protein Coupled

The timing of centrosome separation and the distance moved apart influence the formation of the bipolar spindle, affecting chromosome stability. Epidermal growth factor receptor (EGFR) signaling induces early centrosome separation through downstream G protein-coupled receptor kinase GRK2, which phosphorylates the Hippo pathway component MST2 (Mammalian STE20-like protein kinase 2), in turn allowing NIMA kinase Nek2A activation for centrosomal linker disassembly. However, the mechanisms that counterbalance centrosome disjunction and separation remain poorly understood. We unveil that timely degradation of GRK2 by the E3 ligase Mdm2 limits centrosome separation in the G2. Both knockout expression and catalytic inhibition of Mdm2 result in GRK2 accumulation and enhanced centrosome separation before mitosis onset. Phosphorylation of GRK2 on residue S670 enables a complex pattern of non-K48-linked polyubiquitin chains assembled by Mdm2, which correlate with kinase protein degradation. Remarkably, GRK2-S670A protein fails to phosphorylate MST2 despite overcoming Mdm2-dependent degradation, which results in defective centrosome separation, shorter spindles, and abnormal chromosome congression. Conversely, extra levels of wild-type kinase in the G2 cause increased inter-centrosome distances with longer spindles, also converging in congression issues. Our findings show that the signals enabling activity of the GRK2/MST2/Nek2A axis for separation also switches on Mdm2 degradation of GRK2 to ensure accurate centrosome dynamics and proper mitotic spindle functionality.

scholarly journals Updated Insights on EGFR Signaling Pathways in Glioma

2021 ◽  
Vol 22 (2) ◽  
pp. 587
Author(s):  
Alexandru Oprita ◽  
Stefania-Carina Baloi ◽  
Georgiana-Adeline Staicu ◽  
Oana Alexandru ◽  
Daniela Elise Tache ◽  
...  
Keyword(s):  
Signaling Pathways ◽  
Treatment Strategies ◽  
Growth Factor Receptor ◽  
Standard Of Care ◽  
Egfr Signaling ◽  
Current Standard ◽  
Egfr Amplification ◽  
Epidermal Growth ◽  
New Diagnosis ◽  
Clear Clinical Benefit

Nowadays, due to recent advances in molecular biology, the pathogenesis of glioblastoma is better understood. For the newly diagnosed, the current standard of care is represented by resection followed by radiotherapy and temozolomide administration, but because median overall survival remains poor, new diagnosis and treatment strategies are needed. Due to the quick progression, even with aggressive multimodal treatment, glioblastoma remains almost incurable. It is known that epidermal growth factor receptor (EGFR) amplification is a characteristic of the classical subtype of glioma. However, targeted therapies against this type of receptor have not yet shown a clear clinical benefit. Many factors contribute to resistance, such as ineffective blood–brain barrier penetration, heterogeneity, mutations, as well as compensatory signaling pathways. A better understanding of the EGFR signaling network, and its interrelations with other pathways, are essential to clarify the mechanisms of resistance and create better therapeutic agents.

scholarly journals Dominant Enhancers of Egfr in Drosophila melanogaster: Genetic Links Between the Notch and Egfr Signaling Pathways

Genetics ◽  
1997 ◽  
Vol 147 (3) ◽  
pp. 1139-1153 ◽  
Author(s):  
James V Price ◽  
Edward D Savenye ◽  
David Lum ◽  
Ashton Breitkreutz
Keyword(s):  
Notch Signaling ◽  
Signaling Pathways ◽  
Growth Factor Receptor ◽  
Compound Eyes ◽  
Egfr Signaling ◽  
Wing Vein ◽  
Developmental Context ◽  
Epidermal Growth ◽  
Hypomorphic Alleles ◽  
Complex Signaling

The Drosophila epidermal growth factor receptor (EGFR) is a key component of a complex signaling pathway that participates in multiple developmental processes. We have performed and F1 screen for mutations that cause dominant enhancement of wing vein phenotypes associated with mutations in Egfr. With this screen, we have recovered mutations in Hairless (H), vein, groucho (gro), and three apparently novel loci. All of the E(Egfr)s we have identified show dominant interactions in transheterozygous combinations with each other and with alleles of N or Su(H), suggesting that they are involved in cross-talk between the N and EGFR signaling pathways. Further examination of the phenotypic interactions between Egfr, H, and gro revealed that reductions in Egfr activity enhanced both the bristle loss associated with H mutations, and the bristle hyperplasia and ocellar hypertrophy associated with gro mutations. Double mutant combinations of Egfr and gro hypomorphic alleles led to the formation of ectopic compound eyes in a dosage sensitive manner. Our findings suggest that these E(Egfr)s represent links between the Egfr and Notch signaling pathways, and that Egfr activity can either promote or suppress Notch signaling, depending on its developmental context.

scholarly journals Epidermal growth factor receptor kinase translocation and activation in vivo.

1986 ◽  
Vol 261 (18) ◽  
pp. 8473-8480
Author(s):  
D G Kay ◽  
W H Lai ◽  
M Uchihashi ◽  
M N Khan ◽  
B I Posner ◽  
...  
Keyword(s):  
Epidermal Growth Factor Receptor ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Growth Factor Receptor ◽  
Receptor Kinase ◽  
Epidermal Growth

scholarly journals CG6015 controls spermatogonia transit-amplifying divisions by epidermal growth factor receptor signaling in Drosophila testes

2021 ◽  
Vol 12 (5) ◽  
Author(s):  
Jun Yu ◽  
Qianwen Zheng ◽  
Zhiran Li ◽  
Yunhao Wu ◽  
Yangbo Fu ◽  
...  
Keyword(s):  
Epidermal Growth Factor Receptor ◽  
Stem Cell ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Growth Factor Receptor ◽  
Gene Set Enrichment Analysis ◽  
Germline Stem Cell ◽  
Egfr Signaling ◽  
Egfr Signaling Pathway ◽  
Epidermal Growth

AbstractSpermatogonia transit-amplifying (TA) divisions are crucial for the differentiation of germline stem cell daughters. However, the underlying mechanism is largely unknown. In the present study, we demonstrated that CG6015 was essential for spermatogonia TA-divisions and elongated spermatozoon development in Drosophila melanogaster. Spermatogonia deficient in CG6015 inhibited germline differentiation leading to the accumulation of undifferentiated cell populations. Transcriptome profiling using RNA sequencing indicated that CG6015 was involved in spermatogenesis, spermatid differentiation, and metabolic processes. Gene Set Enrichment Analysis (GSEA) revealed the relationship between CG6015 and the epidermal growth factor receptor (EGFR) signaling pathway. Unexpectedly, we discovered that phosphorylated extracellular regulated kinase (dpERK) signals were activated in germline stem cell (GSC)-like cells after reduction of CG6015 in spermatogonia. Moreover, Downstream of raf1 (Dsor1), a key downstream target of EGFR, mimicked the phenotype of CG6015, and germline dpERK signals were activated in spermatogonia of Dsor1 RNAi testes. Together, these findings revealed a potential regulatory mechanism of CG6015 via EGFR signaling during spermatogonia TA-divisions in Drosophila testes.

Sign in / Sign up

Export Citation Format

Share Document