Role of the Basic, Proline-rich Region of Dynamin in Src Homology 3 Domain Binding and Endocytosis

doi:10.1074/jbc.272.17.11629

Role of the Basic, Proline-rich Region of Dynamin in Src Homology 3 Domain Binding and Endocytosis*

From the ^‡ Cell Biology Group, Worcester Foundation for Biomedical Research, Shrewsbury, Massachusetts 01545 and the
^§ Department of Biochemistry, University of Massachusetts Medical School, Worcester, Massachusetts 01604

^¶ To whom correspondence should be addressed:
Worcester Foundation for Biomedical Research, Cell Biology Group, 222 Maple Ave., Shrewsbury, MA 01545.

Abstract

The GTPase dynamin has been implicated in the regulation of the scission of coated and noncoated pits during the early stages of endocytosis. Various macromolecules including microtubules, acidic phospholipids, and Src homology 3 (SH3) domains have been shown to interact with the basic, proline-rich region of dynamin and act as effectors of its GTPase activity. The interaction of dynamin with SH3 domain-containing proteins is of particular interest since SH3 domains are known to mediate protein-protein interactions in signal transducing complexes. In this study, we have systematically defined three distinct SH3 binding regions within the dynamin proline-rich C terminus. These binding regions conform to either the Class I or II SH3 binding consensus sequence, and their location coincides with a region previously shown to be important in the colocalization of dynamin with clathrin-coated pits. Two of these SH3 binding regions are well conserved among four dynamin isoforms, and we show that the overall binding pattern for SH3 domains is comparable among the isoforms. We also demonstrate that neither transferrin nor platelet-derived growth factor receptor uptake is restored upon removal of the basic, proline-rich region in a dominant negative dynamin GTP binding mutant. Together with earlier evidence from our laboratory, these findings suggest that SH3 domains may serve to target dynamin to coated pits and are not the direct targets of dominant inhibitory mutants of dynamin.

Footnotes

↵* This work was supported by National Institutes of Health Grant GM26701 (to R. B. V.) and postdoctoral training Grant HD07312-10 (to P. M. O.). The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
↵¹ The abbreviations used are:

SH3

Src homology 3

a.a.

amino acid(s)

PLCγ

phospholipase Cγ

PIPES

1,4-piperazinediethanesulfonic acid

PDGFR

platelet-derived growth factor receptor

GST

glutathione S-transferase.
↵² P. M. Okamoto and R. B. Vallee, unpublished observations.
- Received August 26, 1996.
- Revision received January 6, 1997.