The Journal of Biochemistry
Online ISSN : 1756-2651
Print ISSN : 0021-924X
Expression and Characterization of a Very Low Density Lipoprotein Receptor Variant Lacking the O-Linked Sugar Region Generated by Alternative Splicing
Hiroaki IijimaMasaaki MiyazawaJuro SakaiKenta MagooriMitsuko R. ItoHiroyuki SuzukiMasato NoseYutaka KawarabayasiTokuo T. Yamamoto
Author information
JOURNAL FREE ACCESS

1998 Volume 124 Issue 4 Pages 747-755

Details
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 carbo-hydrate 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 β-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-glyco-sylation.

Content from these authors
© The Japanese Biochemical Society
Previous article Next article
feedback
Top