The CH-domain of calponin does not determine the modes of calponin binding to F-actin.
J Mol Biol
; 359(2): 478-85, 2006 Jun 02.
Article
em En
| MEDLINE
| ID: mdl-16626733
ABSTRACT
Many actin-binding proteins have been observed to have a modular architecture. One of the most abundant modules is the calponin-homology (CH) domain, found as tandem repeats in proteins that cross-link actin filaments (such as fimbrin, spectrin and alpha-actinin) or link the actin cytoskeleton to intermediate filaments (such as plectin). In proteins such as the eponymous calponin, IQGAP1, and Scp1, a single CH-domain exists, but there has been some controversy over whether this domain binds to actin filaments. A previous three-dimensional reconstruction of the calponin-F-actin complex has led to the conclusion that the visualized portion of calponin bound to actin belongs to its amino-terminal homology (CH) domain. We show, using a calponin fragment lacking the CH-domain, that this domain is not bound to F-actin, and cannot be positioning calponin on F-actin as hypothesized. Further, using classification methods, we show a multiplicity in cooperative modes of binding of calponin to F-actin, similar to what has been observed for other actin-binding proteins such as tropomyosin and cofilin. Our results suggest that the form and function of the structurally conserved CH-domain found in many other actin-binding proteins have diverged. This has broad implications for inferring function from the presence of structurally conserved domains.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Conformação Proteica
/
Proteínas de Ligação ao Cálcio
/
Actinas
/
Proteínas dos Microfilamentos
Limite:
Animals
Idioma:
En
Revista:
J Mol Biol
Ano de publicação:
2006
Tipo de documento:
Article
País de afiliação:
Estados Unidos