Specificity and autoregulation of Notch binding by tandem WW domains in suppressor of Deltex.
J Biol Chem
; 282(39): 29032-29042, 2007 Sep 28.
Article
em En
| MEDLINE
| ID: mdl-17656366
ABSTRACT
WW domains target proline-tyrosine (PY) motifs and frequently function as tandem pairs. When studied in isolation, single WW domains are notably promiscuous and regulatory mechanisms are undoubtedly required to ensure selective interactions. Here, we show that the fourth WW domain (WW4) of Suppressor of Deltex, a modular Nedd4-like protein that down-regulates the Notch receptor, is the primary mediator of a direct interaction with a Notch-PY motif. A natural Trp to Phe substitution in WW4 reduces its affinity for general PY sequences and enhances selective interaction with the Notch-PY motif via compensatory specificity-determining interactions with PY-flanking residues. When WW4 is paired with WW3, domain-domain association, impeding proper folding, competes with Notch-PY binding to WW4. This novel mode of autoinhibition is relieved by binding of another ligand to WW3. Such cooperativity may facilitate the transient regulatory interactions observed in vivo between Su(dx) and Notch in the endocytic pathway. The highly conserved tandem arrangement of WW domains in Nedd4 proteins, and similar arrangements in more diverse proteins, suggests domain-domain communication may be integral to regulation of their associated cellular activities.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Modelos Moleculares
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Proteínas de Drosophila
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Ubiquitina-Proteína Ligases
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Drosophila melanogaster
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Proteínas de Membrana
Limite:
Animals
Idioma:
En
Revista:
J Biol Chem
Ano de publicação:
2007
Tipo de documento:
Article