Sphingomyelin is an abundant lipid of cell membranes. The subcellular distribution of sphingomyelin remains unexplained. Here we examined staining of sphingomyelin in plasma membranes by two different probes, equinatoxin, a protein from sea anemones, and lysenin, a protein from earthworm. We show that plasma membrane has heterogeneous sphingomyelin pools: a pool stained by only lysenin, by EqtII, and one that is stained by both toxins. The use of the two sphingomyelin-binding probes will provide additional insights into various sphingomyelin- mediated processes in cells.
COBISS.SI-ID: 5025562
Listeriolysin O is the major factor implicated in the escape of Listeria monocytogenes from the phagolysosome. It is not understood entirely how pH specific mechanism of action is achieved by this protein. Here we studied functional and structural properties of this protein and showed that it rapidly aggregates at temperatures above 30 degrees and at neutral pH. The aggregates had the biophysical properties of amyloid. We therefore suggest that LLO spontaneously aggregates at the neutral pH found in the host cell cytosol and that this is a major mechanism of LLO inactivation.
COBISS.SI-ID: 4881690