The Drosophila orthologue of the INT6 onco-protein regulates mitotic microtubule growth and kinetochore structure

Fioranna Renda, Claudia Pellacani, Anton Strunov, Elisabetta Bucciarelli, Valeria Naim, Giuseppe Bosso, Elena Kiseleva, Silvia Bonaccorsi, David J. Sharp, Alexey Khodjakov, Maurizio Gatti, Maria Patrizia Somma

Research output: Contribution to journalArticle

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Abstract

INT6/eIF3e is a highly conserved component of the translation initiation complex that interacts with both the 26S proteasome and the COP9 signalosome, two complexes implicated in ubiquitin-mediated protein degradation. The INT6 gene was originally identified as the insertion site of the mouse mammary tumor virus (MMTV), and later shown to be involved in human tumorigenesis. Here we show that depletion of the Drosophila orthologue of INT6 (Int6) results in short mitotic spindles and deformed centromeres and kinetochores with low intra-kinetochore distance. Poleward flux of microtubule subunits during metaphase is reduced, although fluorescence recovery after photobleaching (FRAP) demonstrates that microtubules remain dynamic both near the kinetochores and at spindle poles. Mitotic progression is delayed during metaphase due to the activity of the spindle assembly checkpoint (SAC). Interestingly, a deubiquitinated form of the kinesin Klp67A (a putative orthologue of human Kif18A) accumulates near the kinetochores in Int6-depleted cells. Consistent with this finding, Klp67A overexpression mimics the Int6 RNAi phenotype. Furthermore, simultaneous depletion of Int6 and Klp67A results in a phenotype identical to RNAi of just Klp67A, which indicates that Klp67A deficiency is epistatic over Int6 deficiency. We propose that Int6-mediated ubiquitination is required to control the activity of Klp67A. In the absence of this control, excess of Klp67A at the kinetochore suppresses microtubule plus-end polymerization, which in turn results in reduced microtubule flux, spindle shortening, and centromere/kinetochore deformation.

Original languageEnglish (US)
Article numbere1006784
JournalPLoS Genetics
Volume13
Issue number5
DOIs
StatePublished - May 1 2017

Fingerprint

Eukaryotic Initiation Factor-3
Kinetochores
kinetochores
Microtubules
microtubules
Drosophila
phenotype
protein
Growth
polymerization
tumor
virus
fluorescence
proteins
Centromere
centromeres
Metaphase
RNA Interference
metaphase
degradation

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Molecular Biology
  • Genetics
  • Genetics(clinical)
  • Cancer Research

Cite this

Renda, F., Pellacani, C., Strunov, A., Bucciarelli, E., Naim, V., Bosso, G., ... Somma, M. P. (2017). The Drosophila orthologue of the INT6 onco-protein regulates mitotic microtubule growth and kinetochore structure. PLoS Genetics, 13(5), [e1006784]. https://doi.org/10.1371/journal.pgen.1006784

The Drosophila orthologue of the INT6 onco-protein regulates mitotic microtubule growth and kinetochore structure. / Renda, Fioranna; Pellacani, Claudia; Strunov, Anton; Bucciarelli, Elisabetta; Naim, Valeria; Bosso, Giuseppe; Kiseleva, Elena; Bonaccorsi, Silvia; Sharp, David J.; Khodjakov, Alexey; Gatti, Maurizio; Somma, Maria Patrizia.

In: PLoS Genetics, Vol. 13, No. 5, e1006784, 01.05.2017.

Research output: Contribution to journalArticle

Renda, F, Pellacani, C, Strunov, A, Bucciarelli, E, Naim, V, Bosso, G, Kiseleva, E, Bonaccorsi, S, Sharp, DJ, Khodjakov, A, Gatti, M & Somma, MP 2017, 'The Drosophila orthologue of the INT6 onco-protein regulates mitotic microtubule growth and kinetochore structure', PLoS Genetics, vol. 13, no. 5, e1006784. https://doi.org/10.1371/journal.pgen.1006784
Renda, Fioranna ; Pellacani, Claudia ; Strunov, Anton ; Bucciarelli, Elisabetta ; Naim, Valeria ; Bosso, Giuseppe ; Kiseleva, Elena ; Bonaccorsi, Silvia ; Sharp, David J. ; Khodjakov, Alexey ; Gatti, Maurizio ; Somma, Maria Patrizia. / The Drosophila orthologue of the INT6 onco-protein regulates mitotic microtubule growth and kinetochore structure. In: PLoS Genetics. 2017 ; Vol. 13, No. 5.
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