Phospholipase C activity-induced fusion of pure lipid model membranes. A freeze fracture study.
The structural effects of in situ production of diacylglycerol by phospholipase C in pure lipid model membranes have been examined by freeze fracture electron microscopy. Phospholipase C-activity induces massive aggregation and fusion of large unilamellar lipid vesicles and leads to the formation of a 'sealed' lipid aggregate; the outer membrane of this aggregate appears to be continuous. In some areas lipid arranges into a honeycomb structure; this structure is probably a precursor of a discontinuous inverted (type II) cubic phase. Similarly, enzyme treatment of multilamellar vesicles leads to extensive membrane fusion and vesiculation. Thus morphological evidence is obtained showing the ability of phospholipase C to induce bilayer destabilization and fusion. It is speculated that phospholipase C-induced membrane fusion involves a type II fusion intermediate induced by diacylglycerol produced locally.
Burger
K N
KN
Institute of Molecular Biology and Medical Biotechnology, University of Utrecht, The Netherlands.
Nieva
J L
JL
Alonso
A
A
Verkleij
A J
AJ
D005614:Freeze Fracturing; D008051:Lipid Bilayers / Q000737:chemistry*; D008854:Microscopy, Electron / Q000379:methods; D010738:Type C Phospholipases / Q000737:chemistry*
D008051:Lipid Bilayers; D010738:Type C Phospholipases