Polysialylation of NCAM by a single enzyme.
Curr Biol
; 6(9): 1188-91, 1996 Sep 01.
Article
en En
| MEDLINE
| ID: mdl-8805371
ABSTRACT
The addition of poly-alpha2,8-N-acetylneuraminic acid (polysialic acid; PSA) to the neural cell adhesion molecule NCAM plays a crucial role in neural development [1-3], neural regeneration [4], and plastic processes in the vertebrate brain associated with neurite outgrowth [5], axonal pathfinding [6], and learning and memory [7,-9]. PSA levels are decreased in people affected by schizophrenia [10], and PSA has been identified as a specific marker for some neuroendocrine and lymphoblastoid tumours [11-13]; expression of PSA on the surface of these tumour cells modulates their metastatic potential [11-13]. Studies aimed at understanding PSA biosynthesis and the dynamics of its production have largely been promoted by the cloning of polysialyltransferases (PST-1 in hamster; PST in human and mouse) [14-16]. However, the number of enzymes involved in the biosynthesis of PSA has not been identified. Using incompletely glycosylated NCAM variants and soluble recombinant glycosyltransferases, we reconstituted the site at which PST-1 acts to polysialylate NCAM in vitro. The data presented here clearly demonstrate that polysialylation of NCAM is catalyzed by a single enzyme, PST-1, and that terminal sialylation of the N-glycan core is sufficient to generate the PSA acceptor site. Our results also show that PST-1 can act on core structures with the terminal sialic acid connected to galactose via an alpha2,3 or alpha2,6 linkage.
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Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Ácidos Siálicos
/
Sialiltransferasas
/
Moléculas de Adhesión de Célula Nerviosa
Límite:
Animals
/
Humans
Idioma:
En
Revista:
Curr Biol
Asunto de la revista:
BIOLOGIA
Año:
1996
Tipo del documento:
Article
País de afiliación:
Alemania