Contrasting membrane interaction mechanisms of AP180 N-terminal homology (ANTH) and epsin N-terminal homology (ENTH) domains.
Epsin and AP180/CALM are endocytotic accessory proteins that have been implicated in the formation of clathrin-coated pits. Both proteins have phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2)-binding domains in their N termini, but these domains are structurally and functionally different. To understand the basis of their distinct properties, we measured the PtdIns(4,5)P2-dependent membrane binding of the epsin N-terminal homology (ENTH) domain and the AP180 N-terminal homology (ANTH) domain by means of surface plasmon resonance and monolayer penetration techniques and also calculated the effect of PtdIns(4,5)P2 on the electrostatic potential of these domains. PtdIns(4,5)P2 enhances the electrostatic membrane association of both domains; however, PtdIns(4,5)P2 binding exerts distinct effects on their membrane dissociation. Specifically, PtdIns(4,5)P2 induces the membrane penetration of the N-terminal alpha-helix of the ENTH domain, which slows the membrane dissociation of the domain and triggers the membrane deformation. These results provide the biophysical explanation for the membrane bending activity of epsin and its ENTH domain.
Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois 60607, USA.
Robert V
RV
Stahelin
Fei
F
Long
Brian J
BJ
Peter
Diana
D
Murray
Pietro
P
De Camilli
Harvey T
HT
McMahon
Wonhwa
W
Cho
D033942:Adaptor Proteins, Vesicular Transport; D001665:Binding Sites; D002352:Carrier Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D002462:Cell Membrane / Q000378:metabolism*; D004705:Endocytosis; D008958:Models, Molecular; D015394:Molecular Structure; D034041:Monomeric Clathrin Assembly Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D016296:Mutagenesis; D009479:Neuropeptides / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D010446:Peptide Fragments / Q000737:chemistry / Q000502:physiology; D019269:Phosphatidylinositol 4,5-Diphosphate / Q000378:metabolism / Q000494:pharmacology; D017433:Protein Structure, Secondary; D011993:Recombinant Fusion Proteins; D055672:Static Electricity; D013329:Structure-Activity Relationship; D020349:Surface Plasmon Resonance; D033921:Vesicular Transport Proteins
D033942:Adaptor Proteins, Vesicular Transport; D002352:Carrier Proteins; D034041:Monomeric Clathrin Assembly Proteins; D009479:Neuropeptides; D010446:Peptide Fragments; D019269:Phosphatidylinositol 4,5-Diphosphate; D011993:Recombinant Fusion Proteins; D033921:Vesicular Transport Proteins; C439023:clathrin assembly protein AP180; C114154:epsin