Polyphosphoinositide inclusion in artificial lipid bilayer vesicles promotes divalent cation-dependent membrane fusion.
AUTOR(ES)
Summers, S A
RESUMO
Recent studies suggest that phosphoinositide kinases may participate in intracellular trafficking or exocytotic events. Because both of these events ultimately require fusion of biological membranes, the susceptibility of membranes containing polyphosphoinositides (PPIs) to divalent cation-induced fusion was investigated. Results of these investigations indicated that artificial liposomes containing PPI or phosphatidic acid required lower Ca2+ concentrations for induction of membrane fusion than similar vesicles containing phosphatidylserine, phosphatidylinositol, or phosphatidylcholine. This trend was first observed in liposomes composed solely of one type of phospholipid. In addition, however, liposomes designed to mimic the phospholipid composition of the endofacial leaflet of plasma membranes (i.e., liposomes composed of combinations of PPI, phosphatidylethanolamine, and phosphatidylcholine) also required lower Ca2+ concentrations for induction of aggregation and fusion. Liposomes containing PPI and phosphatidic acid also had increased sensitivity to Mg(2+)-induced fusion, an observation that is particularly intriguing given the intracellular concentration of Mg2+ ions. Moreover, the fusogenic effects of Ca2+ and Mg2+ were additive in vesicles containing phosphatidylinositol bisphosphate. These data suggest that enzymatic modification of the PPI content of intracellular membranes could be an important mechanism of fusion regulation.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1233808Documentos Relacionados
- Identification of Chlamydia trachomatis Genomic Sequences Recognized by Chlamydial Divalent Cation-Dependent Regulator A (DcrA)
- Cation-dependent Flocculation in a Flavobacterium Species Predominant in Activated Sludge
- Cation-dependent gating of the hyperpolarization-activated cation current in the rabbit sino-atrial node cells.
- The Palmitoyltransferase of the Cation-dependent Mannose 6-Phosphate Receptor Cycles between the Plasma Membrane and Endosomes
- Cation-dependent mannose 6-phosphate receptor contains two internalization signals in its cytoplasmic domain.