Ceramide-enriched membrane domains in red blood cells and the mechanism of sphingomyelinase-induced hot-cold hemolysis.

L.R. MONTES; D.J. LOPEZ; LUIS A. BAGATOLLI; M.J. STONEHOUSE; M.L. VASIL; B.X. WU; Y.A. HANNUN; F. GOÑI; A. ALONSO

BIOCHEMISTRY

AMER CHEMICAL SOC

Lugar: Washington; Año: 2008 vol. 47 p. 11222 - 11222

0006-2960

ot-cold hemolysis is the phenomenon whereby red blood cells, preincubated at 37 degrees C in the presence of certain agents, undergo rapid hemolysis when transferred to 4 degrees C. The mechanism of this phenomenon is not understood. PlcHR 2, a phospholipase C/sphingomyelinase from Pseudomonas aeruginosa, that is the prototype of a new phosphatase superfamily, induces hot-cold hemolysis. We found that the sphingomyelinase, but not the phospholipase C activity, is essential for hot-cold hemolysis because the phenomenon occurs not only in human erythrocytes that contain both phosphatidylcholine (PC) and sphingomyelin (SM) but also in goat erythrocytes, which lack PC. However, in horse erythrocytes, with a large proportion of PC and almost no SM, hot-cold hemolysis induced by PlcHR 2 is not observed. Fluorescence microscopy observations confirm the formation of ceramide-enriched domains as a result of PlcHR 2 activity. After cooling down to 4 degrees C, the erythrocyte ghost membranes ar