Visualization of microtubule disorganization in endothelial cells using photochromic fluorescent protein

Naoto Kawasaki, Akira Nagasaki, Tomoyuki Saito, Takuya Noguchi, Susumu Kudo

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1 Citation (Scopus)


For angiogenesis and wound healing endothelial cells (EC) plays an important role in cell migration and covering over inner vessel wall. Cell migration often induces many polarizations like local distributed and activated molecules, and inhomogeneous membrane viscosity. These polarizations would support variations of signal transduction production at different regions in living cells. It is clear that polarization is associated with microtubule network which is a path for directed molecular transportation. Because of this, observing microtubule structure is a useful approach to investigate polarization scheme in living cells. But within the cell, microtubule organization is not in a stable and uniform structure because microtubule reorganization is derived from repeated tubulin-polymerization and depolymerization. So in order to investigate the mechanisms of microtubule reorganization, measuring the partial behavior of microtubules is crucial task for us. For this reason, we visualized local microtubule using photocromic fluorescent protein called Dronpa. As a result, we confirmed that the fluorescent decay intensity at visualized region associated with microtubule stability and analyzed partial microtubule stability by measuring the time constant τ of the fluorescent decay intensity. On migrating endothelial cell, we selected three regions: 1.Fibrous structure, 2.Tip of microtubule (Plus end) and 3.Rear edge of migrating cell, and measured local microtubule stability, respectively. Comparing time constants among three locations of microtubule, we found that microtubule at Plus end (τpe= 167 ± 15[sec] (mean ± S.E.)) and Rear edge (τRear = 153 ± 16 [sec] were unstable than microtubule constructing Fibrous structure (τfs = 225 ± 17 [sec]). In this study, we established a new method for partial microtubule visualization using photocromic fluorescent protein and using this method we managed to measure local microtubule stability in living cell.

Original languageEnglish
Pages (from-to)595-601
Number of pages7
JournalTransactions of Japanese Society for Medical and Biological Engineering
Issue number6
Publication statusPublished - 2009
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Biomedical Engineering


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