The JD mutation in familial hypercholesterolemia: amino acid substitution in cytoplasmic domain impedes internalization of LDL receptors
CG Davis, MA Lehrman, DW Russell, RGW Anderson… - Cell, 1986 - cell.com
CG Davis, MA Lehrman, DW Russell, RGW Anderson, MS Brown, JL Goldstein
Cell, 1986•cell.comGenomic DNA encompassing the terminal exons of the gene for the low density lipoprotein
(LDL) receptor was isolated from JD, a patient with familial hypercholesterolemia whose
receptor fails to cluster in coated pits. The DNA sequence revealed a substitution of a
cysteine codon for a tyrosine codon at residue 807 in the cytoplasmic domain of the
receptor. We reproduced thissubstitution through oligonucleotidedirected mutagenesis of
the normal human receptor cDNA. Upon transfection into receptor-deficient hamster cells …
(LDL) receptor was isolated from JD, a patient with familial hypercholesterolemia whose
receptor fails to cluster in coated pits. The DNA sequence revealed a substitution of a
cysteine codon for a tyrosine codon at residue 807 in the cytoplasmic domain of the
receptor. We reproduced thissubstitution through oligonucleotidedirected mutagenesis of
the normal human receptor cDNA. Upon transfection into receptor-deficient hamster cells …
Summary
Genomic DNA encompassing the terminal exons of the gene for the low density lipoprotein (LDL) receptor was isolated from JD, a patient with familial hypercholesterolemia whose receptor fails to cluster in coated pits. The DNA sequence revealed a substitution of a cysteine codon for a tyrosine codon at residue 807 in the cytoplasmic domain of the receptor. We reproduced thissubstitution through oligonucleotidedirected mutagenesis of the normal human receptor cDNA. Upon transfection into receptor-deficient hamster cells, the cDNA specified a receptor that bound LDL normally, but entered the cell slowly. Electron microscopy showed that this receptor was distributed diffusely over the cell surface, whereas the receptor produced by the normal cDNA was concentrated in coated pits. These results support the hypothesis that cytoplasmic domains direct receptors to coated pits, thereby determining the high rate of receptor internalization in animal cells.
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