Cold exposure reveals two populations of microtubules in pulmonary endothelia

Cristhiaan D. Ochoa, Troy Stevens, Ron Balczon

Research output: Contribution to journalArticle

20 Scopus citations

Abstract

Microtubules are composed of α-tubulin and β-tubulin dimers. Microtubules yield tubulin dimers when exposed to cold, which reassemble spontaneously to form microtubule fibers at 37°C. However, mammalian neurons, glial cells, and fibroblasts have cold-stable microtubules. While studying the microtubule toxicity mechanisms of the exotoxin Y from Pseudomonas aeruginosa in pulmonary microvascular endothelial cells, we observed that some endothelial microtubules were very difficult to disassemble in the cold. As a consequence, we designed studies to test the hypothesis that microvascular endothelium has a population of cold-stable microtubules. Pulmonary microvascular endothelial cells and HeLa cells (control) were grown under regular cell culture conditions, followed by exposure to an ice-cold water bath and a microtubule extraction protocol. Polymerized microtubules were detected by immunofluorescence confocal microscopy and Western blot analyses. After cold exposure, immunofluorescence revealed that the majority of HeLa cell microtubules disassembled, whereas a smaller population of endothelial cell microtubules disassembled. Immunoblot analyses showed that microvascular endothelial cells express the microtubule cold-stabilizing protein N-STOP (neuronal stable tubule-only polypeptides), and that N-STOP binds to endothelial microtubules after cold exposure, but not if microtubules are disassembled with nocodazole before cold exposure. Hence, pulmonary endothelia have a population of cold-stable microtubules.

Original languageEnglish (US)
Pages (from-to)L132-L138
JournalAmerican Journal of Physiology - Lung Cellular and Molecular Physiology
Volume300
Issue number1
DOIs
StatePublished - Jan 1 2011
Externally publishedYes

Keywords

  • Endothelium
  • Stable tubule-only polypeptides

ASJC Scopus subject areas

  • Physiology
  • Pulmonary and Respiratory Medicine
  • Physiology (medical)
  • Cell Biology

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