Endothelial nitric oxide synthase is segregated from caveolin-1 and localizes to the leading edge of migrating cells

Stefania Bulotta, Andrea Cerullo, Rico Barsacchi, Clara De Palma, Domenicantonio Rotiroti, Emilio Clementi, Nica Borgese

Research output: Contribution to journalArticlepeer-review


The enzyme endothelial Nitric Oxide Synthase (eNOS) is involved in key physiological and pathological processes, including cell motility and apoptosis. It is widely believed that at the cell surface eNOS is localized in caveolae, where caveolin-1 negatively regulates its activity, however, there are still uncertainties on its intracellular distribution. Here, we applied high resolution confocal microscopy to investigate the surface distribution of eNOS in transfected HeLa cells and in human umbilical vein endothelial cells (HUVEC) endogenously expressing the enzyme. In confluent and non-confluent HUVEC and HeLa cells, we failed to detect substantial colocalization between eNOS and caveolin-1 at the cell surface. Instead, in non-confluent cells, eNOS was concentrated in ruffles and at the leading edge of migrating cells, colocalizing with actin filaments and with the raft marker ganglioside GM1, and well segregated from caveolin-1, which was restricted to the posterior region of the cells. Treatments that disrupted microfilaments caused loss of eNOS from the cell surface and decreased Ca2+-stimulated activity, suggesting a role of the cytoskeleton in the localization and function of the enzyme. Our results provide a morphological correlate for the role of eNOS in cell migration and raise questions on the site of interaction between eNOS and caveolin-1.

Original languageEnglish
Pages (from-to)877-889
Number of pages13
JournalExperimental Cell Research
Issue number6
Publication statusPublished - Apr 1 2006


  • Actin cytoskeleton
  • Caveolae
  • Compartmentalization
  • Confocal microscopy
  • Endothelial cells
  • HeLa TetOff cells
  • Membrane ruffles
  • Rafts

ASJC Scopus subject areas

  • Cell Biology


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