Receptors and aging: dedicated to the memory of Paul Ehrlich for the 100th anniversary of his Nobel Prize

Elastin peptides signaling relies on neuraminidase-1-dependent lactosylceramide generation

The sialidase activity of neuraminidase-1 (Neu-1) is responsible for ERK 1/2 pathway activation following binding of elastin peptide on the elastin receptor complex. In this work, we demonstrate that the receptor and lipid rafts colocalize at the plasma membrane. We also show that the disruption of these microdomains as well as their depletion in glycolipids blocks the receptor signaling. Following elastin peptide treatment, the cellular GM₃ level decreases while lactosylceramide (LacCer) content increases consistently with a GM₃/LacCer conversion. The use of lactose or Neu-1 siRNA blocks this process suggesting that the elastin receptor complex is responsible for this lipid conversion. Flow cytometry analysis confirms this elastin peptide-driven LacCer generation. Further, the use of a monoclonal anti-GM₃ blocking antibody shows that GM₃ is required for signaling. In conclusion, our data strongly suggest that Neu-1-dependent GM₃/LacCer conversion is the key event leading to signaling by the elastin receptor complex. As a consequence, we propose that LacCer is an early messenger for this receptor.