Expression and characterization of a very low density lipoprotein receptor variant lacking the O-linked sugar region generated by alternative splicing.
J Biochem
; 124(4): 747-55, 1998 Oct.
Article
em En
| MEDLINE
| ID: mdl-9756619
ABSTRACT
The very low density lipoprotein receptor (VLDLR) gene contains an exon encoding a region of clustered serine and threonine residues immediately outside the membrane-spanning sequence, and this region has been proposed to be the site of clustered O-linked carbohydrate chains. Two forms of VLDLR transcripts, with and without the O-linked sugar region, are generated through alternative splicing. Reverse transcription polymerase chain reaction with RNAs from various rabbit tissues revealed that the VLDLR transcript with the O-linked sugar region (type-1 VLDLR) is the major transcript in heart and muscle, while the VLDLR transcript without the O-linked sugar region (type-2 VLDLR) predominates in non-muscle tissues, including cerebrum, cerebellum, kidney, spleen, adrenal gland, testis, ovary, and uterus. Hamster fibroblasts expressing type-2 VLDLR bound with relatively low affinity to beta-migrating very low density lipoprotein compared with type-1 VLDLR-transfected cells. In contrast, the internalization, dissociation, and degradation of the ligand were not significantly impaired in either type of VLDLR-transfected cell. The receptor proteins in type-2 VLDLR-transfected cells underwent rapid degradation and accumulated in the culture medium, while those in type-1 VLDLR-transfected cells were stable and resistant to proteolytic cleavage. Analysis of the O-linked sugars of both types of transfected cells suggested that the O-linked sugar region is the major site for O-glycosylation.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Transcrição Gênica
/
Variação Genética
/
Receptores de LDL
Limite:
Animals
/
Female
/
Humans
/
Male
Idioma:
En
Revista:
J Biochem
Ano de publicação:
1998
Tipo de documento:
Article