Human SGT interacts with Bag-6/Bat-3/Scythe and cells with reduced levels of either protein display persistence of few misaligned chromosomes and mitotic arrest

Journal Article · Tue Aug 01 04:00:00 EDT 2006 · Experimental Cell Research

DOI:https://doi.org/10.1016/j.yexcr.2006.04.020· OSTI ID:20858008

Winnefeld, Marc ^[1]; Grewenig, Annabel ^[1]; Schnoelzer, Martina ^[2]; Spring, Herbert ^[3]; Knoch, Tobias A ^[4]; Gan, Eugene C ^[5]; Rommelaere, Jean ^[1]; Cziepluch, Celina ^[1]

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1. Infection and Cancer Department, Abteilung F010 and Institut National de la Sante et de la Recherche Medicale U 701, Deutsches Krebsforschungszentrum, Postfach 101949, D-69120 Heidelberg (Germany)
2. Protein Analysis Facility, B100, Deutsches Krebsforschungszentrum, D-69120 Heidelberg (Germany)
3. Analytical Microscopy and Microinjection Facility, V290, Deutsches Krebsforschungszentrum, D-69120 Heidelberg (Germany)
4. Cell Biology and Genetics, Erasmus MC, Dr. Molewaterplein 50, 3015 GE Rotterdam (Netherlands) and Molecular Biophysics, Kirchhoff Institute for Physics, Ruperto-Carola University, D-69120 Heidelberg (Germany)
5. Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710 (United States)

The human small glutamine-rich TPR-containing protein (hSGT) is essential for cell division since RNA-interference-mediated strong reduction of hSGT protein levels causes mitotic arrest (M. Winnefeld, J. Rommelaere, and C. Cziepluch, The human small glutamine-rich TPR-containing protein is required for progress through cell division, Exp. Cell Res. 293 (2004), 43-57). Analysis of HeLa cells expressing a histone 2A-YFP fusion protein revealed the continuous presence of few mislocalized chromosomes close to the spindle poles as possible cause for hSGT depletion-dependent prometaphase arrest. Cells unable to rescue these mislocalized chromosomes into the metaphase plate died at this stage through apoptosis. In order to address hSGT function at the molecular level, mass spectrometry analysis of proteins which co-immunoprecipitated with Flag-tagged hSGT was performed. Thereby, Hsp70 and Bag-6/Bat-3/Scythe were identified as novel hSGT interaction partners while interaction with Hsc70 was confirmed. Results obtained with truncated versions of the hSGT protein revealed that Bag-6/Bat-3/Scythe and Hsp70 or Hsc70 were independently able to form complexes with hSGT. Interaction of hSGT with Hsc70, Hsp70 or Bag-6/Bat-3/Scythe was demonstrated in prometaphase, thereby suggesting a possible role for complexes containing hSGT and distinct (co)-chaperones during mitosis. Finally, cells from populations with reduced levels of Bag-6/Bat-3/Scythe also displayed persistence of mislocalized chromosomes and mitotic arrest, which strongly indicated that hSGT-Bag-6/Bat-3/Scythe complexes could be directly or indirectly required for complete chromosome congression.

• OSTI ID: 20858008
• Journal Information: Experimental Cell Research, Journal Name: Experimental Cell Research Journal Issue: 13 Vol. 312; ISSN 0014-4827; ISSN ECREAL
• Country of Publication: United States
• Language: English

Related Subjects

60 APPLIED LIFE SCIENCES
APOPTOSIS
CHROMOSOMES
GLUTAMINE
HELA CELLS
MASS SPECTROSCOPY
MITOSIS
PROTEINS
RNA