The Appendage Domain of 
-Adaptin Is a High Affinity Binding Site for Dynamin (*)
- From the (1) Departments of Cell Biology and Neuroscience and
- (2) Molecular Genetics and the
- (3) Howard Hughes Medical Institute, the University of Texas Southwestern Medical Center, Dallas, Texas 75235
- § To whom correspondence should be addressed: Dept. of Cell Biology and Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75235.
Abstract
Dynamin is a GTPase that appears to be required for endocytosis. Even though this molecule is known to be in surface-coated
pits, the identity of the resident coat proteins that account for this localization is not known. Here we show that dynamin
is one of three synaptic terminal proteins that bind with specificity to the appendage domain of α-adaptin. Binding is sensitive
to both salt and pH levels but is not affected by nucleotides. Using recombinant dynamin expressed in SF9 cells, we estimate
that the binding affinity is 
200 nM. Binding does not require GTP, and the GTPase activity of dynamin is not stimulated by this interaction. These results suggest
that the COOH terminus of α-adaptin may be a domain within AP2 that mediates the initial interactions between dynamin and
surface-coated pits. This may be an essential step in the regulation of coated pit budding.
Footnotes
-
↵* The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore by hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
-
↵1 The abbreviations used are:
- GST
-
glutathione S-transferase
- GTP
S -
guanosine 5′-3- O-(thio)triphosphate
- AMP-PNP
-
5′-adenylyl β,
-imidodiphosphate
- ATP
S -
adenosine 5′- O-(thiotriphosphate).
- © 1995 by The American Society for Biochemistry and Molecular Biology, Inc.
