Association of Lbc Rho guanine nucleotide exchange factor with alpha-catenin-related protein, alpha-catulin/CTNNAL1, supports serum response factor activation.
J Biol Chem
; 277(47): 45361-70, 2002 Nov 22.
Article
em En
| MEDLINE
| ID: mdl-12270917
ABSTRACT
The Rho GTPase signaling pathway is required for actin cytoskeletal organization and serum response factor-dependent gene transcription. Lbc is a Rho-specific guanine nucleotide exchange factor that contains a modulatory C-terminal region. To elucidate Lbc regulatory mechanism(s), a yeast two-hybrid screen for proteins that interact with the Lbc C-terminal region was carried out, resulting in multiple isolation of cDNAs encoding the same 734-amino acid Lbc interacting protein. The Lbc interacting protein has homology with the alpha-catenin cell adhesion component and is identical to the alpha-catenin-like alpha-catulin protein of unknown function. The human alpha-catulin gene (CTNNAL1) maps to 9q31-32. Here we identify the predicted endogenous alpha-catulin product, document alpha-catulin and Lbc co-expression in multiple human cell lines, and show alpha-catulin and Lbc subcellular co-fractionation and intracellular localization. The required regions for Lbc and alpha-catulin interaction were mapped, and complex formation between Lbc and alpha-catulin in mammalian cells was detected. Functionally, alpha-catulin co-expression leads to increased Lbc-induced serum response factor activation in vivo as measured by a transcriptional reporter assay. Furthermore, alpha-catulin co-expression enhances Lbc-induced GTP-Rho formation in vivo. These results support the concept that the recently identified alpha-catulin protein may modulate Rho pathway signaling in vivo by providing a scaffold for the Lbc Rho guanine nucleotide exchange factor.
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Bases de dados:
MEDLINE
Assunto principal:
Proteínas Proto-Oncogênicas
/
Fatores de Troca do Nucleotídeo Guanina
/
Proteínas do Citoesqueleto
/
Fator de Resposta Sérica
Tipo de estudo:
Prognostic_studies
/
Risk_factors_studies
Limite:
Humans
Idioma:
En
Revista:
J Biol Chem
Ano de publicação:
2002
Tipo de documento:
Article
País de afiliação:
Estados Unidos