A ubiquitin-interacting motif (UIM) is essential for Eps15 and Eps15R ubiquitination.
An important negative control mechanism in the signaling of epidermal growth factor (EGF) is the endocytosis and subsequent degradation of activated EGF receptors. Eps15 and its related partner Eps15R play a key role in clathrin-mediated endocytosis of transmembrane receptors. Upon EGF stimulation of the cell, Eps15 becomes both phosphorylated on tyrosine residues and monoubiquitinated. Although tyrosine phosphorylation of Eps15 has been implicated in EGF receptor internalization, the function of Eps15 ubiquitination is not known. Using a mutational approach, we have found that the second ubiquitin-interacting motif (UIM) of Eps15 and Eps15R is essential for their ubiquitination. This UIM partially overlaps with the recently characterized nuclear export signal in Eps15. We show that these two overlapping motifs have different structural requirements with respect to nuclear export signal versus ubiquitination signal activity. Our data demonstrate that the UIM does not contain the ubiquitin acceptor site but functions as a recruitment site for the ubiquitination machinery leading to the monoubiquitination of both Eps15 and Eps15R.
Klapisz
Elsa
E
Molecular Cell Biology, Institute of Biomembranes, Universiteit Utrecht, Padualaan 8, 3584 CH Utrecht, The Netherlands.
Sorokina
Irina
I
Lemeer
Simone
S
Pijnenburg
Marian
M
Verkleij
Arie J
AJ
van Bergen en Henegouwen
Paul M P
PM
D021581:Active Transport, Cell Nucleus; D048868:Adaptor Proteins, Signal Transducing; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002135:Calcium-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D002460:Cell Line; D004705:Endocytosis; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D008969:Molecular Sequence Data; D010750:Phosphoproteins / Q000737:chemistry / Q000378:metabolism*; D025801:Ubiquitin / Q000378:metabolism*
D048868:Adaptor Proteins, Signal Transducing; D002135:Calcium-Binding Proteins; C486206:EPS15 protein, human; C094318:Eps15-rs protein, mouse; D047908:Intracellular Signaling Peptides and Proteins; D010750:Phosphoproteins; D025801:Ubiquitin