Myristyl trimethyl ammonium bromide and octadecyl trimethyl ammonium bromide are surface-active small molecule dynamin inhibitors that block endocytosis mediated by dynamin I or dynamin II.
Dynamin is a GTPase enzyme involved in membrane constriction and fission during endocytosis. Phospholipid binding via its pleckstrin homology domain maximally stimulates dynamin activity. We developed a series of surface-active small-molecule inhibitors, such as myristyl trimethyl ammonium bromide (MiTMAB) and octadecyltrimethyl ammonium bromide (OcTMAB), and we now show MiTMAB targets the dynamin-phospholipid interaction. MiTMAB inhibited dynamin GTPase activity, with a Ki of 940 +/- 25 nM. It potently inhibited receptor-mediated endocytosis (RME) of transferrin or epidermal growth factor (EGF) in a range of cells without blocking EGF binding, receptor number, or autophosphorylation. RME inhibition was rapidly reversed after washout. The rank order of potency for a variety of MiTMAB analogs on RME matched the rank order for dynamin inhibition, suggesting dynamin recruitment to the membrane is a primary cellular target. MiTMAB also inhibited synaptic vesicle endocytosis in rat brain nerve terminals (synaptosomes) without inducing depolarization or morphological defects. Therefore, the drug rapidly and reversibly blocks multiple forms of endocytosis with no acute cellular damage. The unique mechanism of action of MiTMAB provides an important tool to better understand dynamin-mediated membrane trafficking events in a variety of cells.
Quan
Annie
A
Cell Signaling Unit, Children's Medical Research Institute, University of Sydney, Sydney, NSW 2145, Australia.
McGeachie
Andrew B
AB
Keating
Damien J
DJ
van Dam
Ellen M
EM
Rusak
Jenny
J
Chau
Ngoc
N
Malladi
Chandra S
CS
Chen
Chen
C
McCluskey
Adam
A
Cousin
Michael A
MA
Robinson
Phillip J
PJ
D000473:Alkanes / Q000737:chemistry / Q000494:pharmacology*; D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D034284:Dynamin I / Q000037:antagonists & inhibitors* / Q000502:physiology; D034285:Dynamin II / Q000037:antagonists & inhibitors* / Q000502:physiology; D004705:Endocytosis / Q000187:drug effects* / Q000502:physiology*; D006367:HeLa Cells; D006801:Humans; D000644:Quaternary Ammonium Compounds / Q000737:chemistry / Q000494:pharmacology*; D012756:Sheep; D013501:Surface-Active Agents / Q000737:chemistry / Q000494:pharmacology; D050337:Trimethyl Ammonium Compounds / Q000737:chemistry / Q000494:pharmacology*
D000473:Alkanes; D000644:Quaternary Ammonium Compounds; D013501:Surface-Active Agents; D050337:Trimethyl Ammonium Compounds; C518260:octadecyltrimethylammonium bromide; D034284:Dynamin I; D034285:Dynamin II; C009410:tetradecyltrimethylammonium