Molecular portrait of lens gap junction protein MP70.
J Struct Biol
; 103(3): 204-11, 1990 May.
Article
en En
| MEDLINE
| ID: mdl-2175636
A 70-kDa membrane protein (MP70) is a component of the lens fiber gap junctions. Its membrane topology and its N-terminal sequence are similar to those of the connexin family of proteins. Some features of MP70 containing fiber gap junctions are, however, distinct from gap junctions in other mammalian tissues: (i) Lens connexons form crystalline arrays only after cleavage of junctional proteins in vitro. These hexagonal arrays have a periodicity of 13.6 nm which is significantly larger than the 8- 9-nm spacing of liver and heart gap junctions. (ii) Lens fiber gap junctions dissociate in low concentrations of nonionic detergent and this provides an avenue to purify MP70 directly from a membrane mixture. Isolated MP70 in the form of 17 S structures has an appearance consistent with connexon pairs. (iii) The C-terminal half of MP70 is cleaved in situ by a lens endogenous calcium-dependent protease. The processed from MP38 remains in the membrane and is abundant in the central region of the lens. A testable hypothesis for MP70 function is presented.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Glicoproteínas de Membrana
/
Proteínas del Ojo
Tipo de estudio:
Observational_studies
/
Risk_factors_studies
Idioma:
En
Revista:
J Struct Biol
Asunto de la revista:
BIOLOGIA MOLECULAR
Año:
1990
Tipo del documento:
Article
País de afiliación:
Nueva Zelanda
Pais de publicación:
Estados Unidos