A Deubiquitinating Enzyme UBPY Interacts with the Src Homology 3 Domain of Hrs-binding Protein via a Novel Binding Motif PX(V/I)(D/N)RXXKP

doi:10.1074/jbc.M007251200

A Deubiquitinating Enzyme UBPY Interacts with the Src Homology 3 Domain of Hrs-binding Protein via a Novel Binding Motif PX(V/I)(D/N)RXXKP*

From the Department of Biological Sciences, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Nagatsuta, Midori-ku, Yokohama 226-8501, Japan

Abstract

Hrs-binding protein (Hbp) is a Src homology 3 (SH3) domain-containing protein that tightly associates with Hrs. Hbp together with Hrs is thought to play a regulatory role in endocytic trafficking of growth factor-receptor complexes through early endosomes. Association of Hbp with a binding partner(s) via the SH3 domain seems to be essential for Hbp to exert its function. In this study, we searched for Hbp-binding proteins by a far Western screening and isolated a mouse cDNA clone encoding a deubiquitinating enzyme mUBPY as an Hbp SH3-binding protein. mUBPY has two Hbp-SH3 domain binding sites. Mutagenic analysis identified a consensus sequence PX(V/I)(D/N)RXXKP as the Hbp-SH3 domain binding motif. It is a novel SH3-binding motif and does not contain the canonical proline-rich consensus binding motif, PXXP. Ubiquitination of growth factor receptors is thought to regulate their intracellular degradation. Thus, UBPY may play a regulatory role in the degradation by interaction with the SH3 domain of Hbp via the novel SH3-binding motif.

Footnotes

↵* This work was supported in part by research grants from the Ministry of Education, Science, Sports and Culture of Japan.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.

The nucleotide sequence(s) reported in this paper has been submitted to the GenBank™/EMBL Data Bank with accession number(s) .
↵‡ To whom correspondence should be addressed: Dept. of Biological Sciences, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan. Tel.: 81-45-924-5701; Fax: 81-45-924-5771; E-mail: nkitamur@bio.titech.ac.jp.
Published, JBC Papers in Press, September 11, 2000, DOI 10.1074/jbc.M007251200
Abbreviations:

Hbp

Hrs-binding protein

SH3

Src homology 3

SBM

SH3 domain binding motif

RACE

rapid amplification of cDNA ends

mUBPY

mouse UBPY

GST

glutathione S-transferase

PCR

polymerase chain reaction

HA

hemagglutinin

UBP

ubiquitin-specific protease

GAB

Grb2-associated binder

BLNK

B cell linker protein
- Received August 10, 2000.
The American Society for Biochemistry and Molecular Biology, Inc.