Proteomic profiling and characterization of the [gamma]-tubulin ring complex

Abstract Recently, two cases of complete remission of classical Hodgkin lymphoma (cHL) and follicular lymphoma (FL) after SARS-CoV-2 infection were reported. However, the precise molecular mechanism of this rare event is yet to be understood. Here, we hypothesize a potential anti-tumor immune response of SARS-CoV-2 and based on computational approach show that (i) SARS-CoV-2 Spike-RBD may bind to extracellular domains of CD15, CD27, CD45, and CD152 receptors of cHL or FL, (ii) upon internalization, SARS-CoV-2 membrane (M) protein and Orf3a may bind to gamma-tubulin complex component 3 (GCP3) at its tubulin gamma-1 chain (TUBG1) binding site, (iii) M protein may also interact with TUBG1 blocking its binding to GCP3, (iv) both M and Orf3a may render the GCP2-GCP3 lateral binding where M possibly interacts with GCP2 at its GCP3 binding site and Orf3a to GCP3 at its GCP2 interacting residues, (v) interactions of M and Orf3a with these gamma-tubulin ring complex components potentially block the initial process of microtubule nucleation, leading to cell cycle arrest and apoptosis, (vi) Spike-RBD may also interact with and block PD-1 signaling similar to pembrolizumab and nivolumab like monoclonal antibodies and may induce B-cell apoptosis and remission, (vii) finally, the TRADD interacting PVQLSY motif of Epstein-Barr virus LMP-1, that is responsible for NF-kB mediated oncogenesis, potentially interacts with SARS-CoV-2 Mpro, nsp7, nsp10, and Spike proteins and may regulate the LMP-1 mediated cell proliferation. Taken together, our results suggest a possible therapeutic potential of SARS-CoV-2 in proliferative disorders.

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Characterization of a New γTuRC Subunit with WD Repeats

Molecular Biology of the Cell ◽

10.1091/mbc.e02-01-0034 ◽

2003 ◽

Vol 14 (3) ◽

pp. 1017-1026 ◽

Cited By ~ 36

Author(s):

Ruwanthi N. Gunawardane ◽

Ona C. Martin ◽

Yixian Zheng

Keyword(s):

Microtubule Assembly ◽

Guanine Nucleotide ◽

Protein Subunits ◽

Multiple Protein ◽

Tubulin Binding ◽

Ring Complex ◽

Signature Sequences ◽

Complete Set ◽

Wd Repeats

The γ-tubulin ring complex (γTuRC), consisting of multiple protein subunits, can nucleate microtubule assembly. Although many subunits of the γTuRC have been identified, a complete set remains to be defined in any organism. In addition, how the subunits interact with each other to assemble into γTuRC remains largely unknown. Here, we report the characterization of a novel γTuRC subunit, Drosophila gamma ring protein with WD repeats (Dgp71WD). With the exception of γ-tubulin, Dgp71WD is the only γTuRC component identified to date that does not contain the grip motifs, which are signature sequences conserved in γTuRC components. By performing immunoprecipitations after pair-wise coexpression in Sf9 cells, we show that Dgp71WD directly interacts with the grip motif–containing γTuRC subunits, Dgrips84, 91, 128, and 163, suggesting that Dgp71WD may play a scaffolding role in γTuRC organization. We also show that Dgrips128 and 163, like Dgrips84 and 91, can interact directly with γ-tubulin. Coexpression of any of these grip motif–containing proteins with γ-tubulin promotes γ-tubulin binding to guanine nucleotide. In contrast, in the same assay Dgp71WD interacts with γ-tubulin but does not facilitate nucleotide binding.

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Venom characterization of the three species of Ophryacus and proteomic profiling of O. sphenophrys unveils Sphenotoxin, a novel Crotoxin-like heterodimeric β-neurotoxin

Journal of Proteomics ◽

10.1016/j.jprot.2018.09.002 ◽

2019 ◽

Vol 192 ◽

pp. 196-207 ◽

Cited By ~ 3

Author(s):

Edgar Neri-Castro ◽

Bruno Lomonte ◽

Mariel Valdés ◽

Roberto Ponce-López ◽

Melisa Bénard-Valle ◽

...

Keyword(s):

Proteomic Profiling

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Identification of an Spc110p-related protein in vertebrates

Journal of Cell Science ◽

10.1242/jcs.110.20.2533 ◽

1997 ◽

Vol 110 (20) ◽

pp. 2533-2545 ◽

Cited By ~ 1

Author(s):

A.M. Tassin ◽

C. Celati ◽

M. Paintrand ◽

M. Bornens

Keyword(s):

Mammalian Cells ◽

Spindle Pole Body ◽

Spindle Pole ◽

Partial Purification ◽

Related Protein ◽

Microtubule Nucleation ◽

Pole Body ◽

Egg Extract ◽

Ring Complex ◽

Gamma Tubulin

Although varying in size and complexity, centrosomes have conserved functions throughout the evolutionary range of eukaryotes, and thus may display conserved components. In this work, we took advantage of the recent advances in the isolation of the budding yeast spindle pole body, the development of specific immunological probes and the molecular characterisation of genes involved in spindle pole body duplication or assembly. Screening a monoclonal antibody library against Saccharomyces cerevisiae spindle pole body components, we found that two monoclonal antibodies, directed against two different parts of the yeast Spc110p, decorate the centrosome from mammalian cells in an asymmetrical manner. Western blot experiments identified a 100 kDa protein specifically enriched in centrosome preparations from human cells. This protein is phosphorylated during mitosis and is tightly associated with the centrosome: only denaturing conditions such as 8 M urea were able to solubilise it. Purified immunoglobulins directed against Spc110p inhibit microtubule nucleation on isolated human centrosomes, using brain phosphocellulose-tubulin or Xenopus egg extract tubulin. This result suggested that the centrosomal 100 kDa protein could be involved in a microtubule nucleation complex. To test this hypothesis, we turned to Xenopus species, in which mAb anti-Spc110p decorated centrosomes from somatic cells and identified a 116 kDa protein in egg extract. We performed a partial purification of the gamma-tubulin-ring complex from egg extract. Sucrose gradient sedimentation, immunoprecipitation and native gels demonstrated that the Xenopus 116 kDa protein and gamma-tubulin were found in the same complex. Altogether, these results suggest the existence of an yeast Spc110-related protein in vertebrate centrosomes which is involved in microtubule nucleation.

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