TY - JOUR
T1 - Expression and characterization of a very low density lipoprotein receptor variant lacking the O-linked sugar region generated by alternative splicing
AU - Iijima, Hiroaki
AU - Miyazawa, Masaaki
AU - Sakai, Juro
AU - Magoori, Kenta
AU - Ito, Mitsuko R.
AU - Suzuki, Hiroyuki
AU - Nose, Masato
AU - Kawarabayasi, Yutaka
AU - Yamamoto, Tokuo T.
PY - 1998/10
Y1 - 1998/10
N2 - 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 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-glycosylation.
AB - 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 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-glycosylation.
KW - Lipoprotein
KW - O-linked sugar
KW - Splicing variant
KW - VLDL receptor
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U2 - 10.1093/oxfordjournals.jbchem.a022175
DO - 10.1093/oxfordjournals.jbchem.a022175
M3 - Article
C2 - 9756619
AN - SCOPUS:0031792704
VL - 124
SP - 747
EP - 755
JO - Journal of Biochemistry
JF - Journal of Biochemistry
SN - 0021-924X
IS - 4
ER -