Details

Autor(en) / Beteiligte

• Alm, Ida
• García-Linares, Sara
• Gavilanes, José G.
• Martínez-del-Pozo, Álvaro
• Slotte, J. Peter

Titel

Cholesterol stimulates and ceramide inhibits Sticholysin II-induced pore formation in complex bilayer membranes

Ist Teil von

• Biochimica et biophysica acta, 2015-04, Vol.1848 (4), p.925-931

Ort / Verlag

Netherlands: Elsevier B.V

Erscheinungsjahr

2015

Quelle

Free E-Journal (出版社公開部分のみ）

Beschreibungen/Notizen

• The pore forming capacity of Sticholysin II (StnII; isolated from Stichodactyla helianthus) in bilayer membranes containing 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), palmitoylsphingomyelin (PSM) and either cholesterol or palmitoyl ceramide (PCer) has been examined. The aim of the study was to elucidate how the presence of differently ordered PSM domains affected StnII oligomerization and pore formation. Cholesterol is known to enhance pore formation by StnII, and our results confirmed this and provide kinetic information for the process. The effect of cholesterol on bilayer permeabilization kinetics was concentration-dependent. In the concentration regime used (2.5–10nmol cholesterol in POPC:PSM 80:20 by nmol), cholesterol also increased the acyl chain order in the fluid PSM domain and thus decreased bilayer fluidity, suggesting that fluidity per se was not responsible for cholesterol's effect. Addition of PCer (2.5–10nmol) to the POPC:PSM (80:20 by nmol) bilayers attenuated StnII-induced pore formation, again in a concentration-dependent fashion. This addition also led to the formation of a PCer-rich gel phase. Addition of cholesterol to PCer-containing membranes could partially reduce the inhibitory effect of PCer on StnII pore formation. We conclude that the physical state of PSM (as influenced by either cholesterol or PCer) affected StnII binding and pore formation under the conditions examined. [Display omitted] •The effect of cholesterol or ceramide on sticholysin II pore formation was examined.•In POPC/16:0 sphingomyelin 4:1 vesicles, cholesterol (up to 10mol%) activated calcein release (pore formation).•Under corresponding conditions, 10mol% palmitoylceramide was inhibitory.•Cholesterol was shown to partially attenuate ceramide's effect on pore formation.