Characterization of Mas-7-induced pore formation in SK-N-BE(2)C human neuroblastoma cells.
Mastoparan, a peptide toxin from wasp venome, mimics receptors by stimulating the GTPase activity of guanine nucleotide binding proteins and the G-protein-coupled phospholipase C (PLC). By using Mas-7, the active analog of mastoparan, we showed that it makes pores in the plasma membrane. Treatment with Mas-7 but not Mas-17, the inactive analog, produced a concentration-dependent rise in intracellular Ca2+ concentration ([Ca2+]i) and facilitated the uptake of ethidium bromide (EtBr) (314 Da) to a sustained level during the stimulation. In addition, Mas-7 triggered the influx of lucifer yellow (457 Da), while it did not induce the influx of fura-2 (831 Da) and Evans blue (961 Da). However, the Mas-7-induced permeability was selectively prevented by the addition of La3+, Ni2+, and Co2+, but not Cd2+. This blocking activity was concentration-dependent. While the stimulatory effect of Mas-7 on PLC activity was dependent on extracellular Ca2+, the pore forming activity of Mas-7 was not effected by removal of extracellular Ca2+. These results, therefore, suggest that the mastoparan's action in pore formation is independent from its action in PLC stimulation and is negatively effected by inorganic cations.
Suh
B C
BC
Department of Life Science, Pohang University of Science and Technology, Korea.
Lee
I S
IS
Chae
H D
HD
Han
S
S
Kim
K T
KT
D002118:Calcium / Q000037:antagonists & inhibitors / Q000493:pharmacokinetics / Q000494:pharmacology; D002462:Cell Membrane / Q000187:drug effects* / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D004996:Ethidium / Q000493:pharmacokinetics; D005110:Extracellular Space / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D007811:Lanthanum / Q000494:pharmacology; D009447:Neuroblastoma / Q000378:metabolism* / Q000473:pathology; D010455:Peptides / Q000008:administration & dosage / Q000494:pharmacology*; D014407:Tumor Cells, Cultured / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D010738:Type C Phospholipases / Q000187:drug effects / Q000378:metabolism
D036341:Intercellular Signaling Peptides and Proteins; C084070:Mas7 protein, synthetic; D010455:Peptides; D007811:Lanthanum; D010738:Type C Phospholipases; D004996:Ethidium; D002118:Calcium