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ROLE OF PHOSPHORYLATION OF THE CYTOPLASMIC DOMAIN OF THE α 2 ‐MACROGLOBULIN RECEPTOR (LRP)
Author(s) -
Djordjevic Julianne T.,
Waterkeyn Jacqui G.,
Hennessy Karen L.,
Stanley Keith K.
Publication year - 2000
Publication title -
cell biology international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.932
H-Index - 77
eISSN - 1095-8355
pISSN - 1065-6995
DOI - 10.1006/cbir.2000.0561
Subject(s) - ldl receptor , phosphorylation , microbiology and biotechnology , cytoplasm , receptor , staurosporine , biology , chemistry , biochemistry , lipoprotein , protein kinase c , cholesterol
The low density lipoprotein receptor‐related protein (α 2 MR/LRP) is a cell surface receptor which is present on most cells and tissues. We show that the 85kDa subunit, containing the transmembrane region and cytoplasmic domain is phosphorylated in vivo . Comparison of the phosphorylation of the low density lipoprotein receptor (LDLR) with a chimeric receptor containing the cytoplasmic domain of the α 2 MR/LRP (LDLR/LRP) showed that phosphorylation is exclusive to the cytoplasmic domain. Staurosporine, a general kinase inhibitor, resulted in a 40% lowering of phosphorylation of LDLR/LRP, but did not give rise to measurable changes in its membrane traffic in MDCK cells. The role of phosphorylation on degradation of the receptor was studied using inhibitors of lysosomal and proteasomal degradation. These studies showed that LDLR/LRP was rapidly turned over by proteasomal degradation but that this turnover was also not a consequence of phosphorylation.