A cytokine-cytokine interaction in the assembly of higher-order structure and activation of the interleukine-3:receptor complex.
PLoS One
; 4(4): e5188, 2009.
Article
en En
| MEDLINE
| ID: mdl-19352505
ABSTRACT
Interleukine-3 (IL-3) binds its receptor and initiates a cascade of signaling processes that regulate the proliferation and differentiation of hematopoietic cells. To understand the detailed mechanisms of IL-3 induced receptor activation, we generated a homology model of the IL-3receptor complex based on the closely related crystal structure of the GM-CSFreceptor complex. Model-predicted interactions between IL-3 and its receptor are in excellent agreement with mutagenesis data, which validate the model and establish a detailed view of IL-3receptor interaction. The homology structure reveals an IL-3IL-3 interaction interface in a higher-order complex modeled after the dodecamer of the GM-CSFreceptor complex wherein an analogous GM-CSFGM-CSF interface is also identified. This interface is mediated by a proline-rich hydrophobic motif (PPLPLL) of the AA' loop that is highly exposed in the structure of isolated IL-3. Various experimental data suggest that this motif is required for IL-3 function through receptor-binding independent mechanisms. These observations are consistent with structure-function studies of the GM-CSFreceptor complex showing that formation of the higher-order cytokinereceptor complex is required for signaling. However, a key question not answered from previous studies is how cytokine binding facilitates the assembly of the higher-order complex. Our studies here reveal a potential cytokine-cytokine interaction that participates in the assembly of the dodecamer complex, thus linking cytokine binding to receptor activation.
Texto completo:
1
Base de datos:
MEDLINE
Asunto principal:
Citocinas
/
Receptores de Interleucina-3
Tipo de estudio:
Prognostic_studies
Idioma:
En
Revista:
PLoS One
Asunto de la revista:
CIENCIA
/
MEDICINA
Año:
2009
Tipo del documento:
Article
País de afiliación:
Estados Unidos