A tyrosine residue in the juxtamembrane segment of the platelet-derived growth factor beta-receptor is critical for ligand-mediated endocytosis
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The importance of tyrosine residues in ligand-mediated endocytosis of the platelet-derived growth factor beta-receptor was analyzed using a series of tyrosine residue-mutated beta-receptors, which together cover all of the tyrosine residues in the juxtamembrane segment, the kinase insert, and the carboxyl-terminal tail; also certain of the tyrosine residues within the first and second parts of the kinase domain were examined. Of all of these tyrosine residues, only Tyr-579 seemed to be important for internalization, since mutation of this residue resulted in substantial reduction in the rate of ligand-induced receptor internalization (approximately 60% of the wild-type level). Replacement of Tyr-579 by either an aromatic (Phe) or a nonaromatic (Asp) residue reduced the efficiency of the mutant receptors in internalization to the same extent, suggesting that the role of Tyr-579 in the beta-receptor is different from that of the previously described tyrosine-based internalization motifs, which were first determined for the low density lipoprotein receptor. Tyr-579 has been found to be an autophosphorylation site in the beta-receptor. Moreover, the internalization rate of a kinase negative receptor mutant was not altered by the additional mutation of Tyr-579. Thus, it is likely that phosphorylation of Tyr-579 is important for ligand-induced internalization of the beta-receptor.
|Research areas and keywords||
Subject classification (UKÄ) – MANDATORY
|Journal||Journal of Biological Chemistry|
|Publication status||Published - 1994|
The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Experimental Clinical Chemistry (013016010)