TY - JOUR
T1 - Mechanisms of leakage
AU - Nir, Shlomo
PY - 1995
Y1 - 1995
N2 - Two mechanisms of leakage from liposomes are discussed, (i) Cations such as Ca2+ induce graded release whose rate depends mainly on vesicle collisions and is associated in the case of several acidic phospholipids with fusion events. A certain degree of leakage also occurs in between collisions. Consequently, the leakage per fusion is reduced at larger lipid and Ca concentrations, (n) Certain peptides induce leakage by pore formation, which shows selectivity to the size of the entrapped molecules and occurs by an all or none mechanism; vesicles either leak or retain all of their contents. A model for final extents and kinetics of leakage due to pore forming peptides is described. This model assumes that pore forming peptides become incorporated into the vesicle bilayer and aggregate to form a pore. Recent developments in the model enable considerations of a reversible or irreversible surface aggregation of peptides. Results of final extents and kinetics of leakage induced by pore forming peptides can be well explained and predicted by this formalism. Studies demonstrate that Ca can play a dual role in affecting leakage. A case is presented where Ca + inhibits and can even arrest pore formation by a peptide, while promoting vesicle fusion. Conversely, formation of pore structures by a peptide can inhibit vesicle fusion.
AB - Two mechanisms of leakage from liposomes are discussed, (i) Cations such as Ca2+ induce graded release whose rate depends mainly on vesicle collisions and is associated in the case of several acidic phospholipids with fusion events. A certain degree of leakage also occurs in between collisions. Consequently, the leakage per fusion is reduced at larger lipid and Ca concentrations, (n) Certain peptides induce leakage by pore formation, which shows selectivity to the size of the entrapped molecules and occurs by an all or none mechanism; vesicles either leak or retain all of their contents. A model for final extents and kinetics of leakage due to pore forming peptides is described. This model assumes that pore forming peptides become incorporated into the vesicle bilayer and aggregate to form a pore. Recent developments in the model enable considerations of a reversible or irreversible surface aggregation of peptides. Results of final extents and kinetics of leakage induced by pore forming peptides can be well explained and predicted by this formalism. Studies demonstrate that Ca can play a dual role in affecting leakage. A case is presented where Ca + inhibits and can even arrest pore formation by a peptide, while promoting vesicle fusion. Conversely, formation of pore structures by a peptide can inhibit vesicle fusion.
UR - http://www.scopus.com/inward/record.url?scp=0028786389&partnerID=8YFLogxK
U2 - 10.3109/08982109509012687
DO - 10.3109/08982109509012687
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AN - SCOPUS:0028786389
SN - 0898-2104
VL - 5
SP - 855
EP - 871
JO - Journal of Liposome Research
JF - Journal of Liposome Research
IS - 4
ER -