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Vascular smooth muscle cell polyploidization involves changes in chromosome passenger proteins and an endomitotic
Yuka Nagata1, Matthew R Jones, Hao G Nguyen
1Recognition and Formation, Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), Japan.
Experimental Cell Research
|April 9, 2005
Summary
Vascular smooth muscle cells (VSMC) polyploidization involves an endomitotic cell cycle with defects in chromosome segregation. Aberrant activity of chromosomal passenger proteins, particularly Survivin, contributes to this process.
Area of Science:
- Cell Biology
- Molecular Biology
- Vascular Biology
Background:
- Vascular smooth muscle cell (VSMC) polyploidization is a normal developmental process.
- This cell cycle is enhanced under physiological stress.
- The underlying mechanisms of VSMC polyploidization remain largely unexplored.
Purpose of the Study:
- To investigate the cell cycle mechanisms of vascular smooth muscle cell polyploidization.
- To identify key regulators involved in this process.
Main Methods:
- Time-lapse video imaging of primary VSMCs.
- Immunofluorescence analyses to examine chromosomal passenger proteins.
- Assessment of protein localization and phosphorylation.
Main Results:
- VSMCs undergo an endomitotic-type cell cycle with defects in sister chromatid separation/segregation and cytokinesis.
- Aurora B and inner centromere protein show normal localization, while Survivin exhibits aberrant localization in VSMCs.
- Survivin deficiency correlates with impaired vimentin phosphorylation and increased polyploidization.
Conclusions:
- Aberrant chromosomal passenger protein activity, specifically Survivin dysfunction, is linked to endomitosis and polyploidization in VSMCs.
- Ectopic expression of Survivin inhibits VSMC polyploidization.
- These findings elucidate novel mechanisms in VSMC cell cycle regulation.