Phosphorylation of the human transferrin receptor by protein kinase C is not required for endocytosis and recycling in mouse 3T3 cells.
AUTOR(ES)
Zerial, M
RESUMO
We have investigated the role of phosphorylation in the endocytosis of the human transferrin receptor (TR) by replacing its phosphorylation site, Ser24, with Ala through site-directed mutagenesis of the TR cDNA. The TR Ala24 mutant expressed in mouse 3T3 cells was not phosphorylated, even following stimulation of protein kinase C by phorbol ester. However, in spite of this defect the mutant was efficiently endocytosed and recycled back to the plasma membrane with kinetics similar to those of TR and a control mutant TR Ala63. Thus, these results confirm earlier results by Davis et al. (1986, J. Biol. Chem., 261-9034-9041) that Ser24 of human TR is the phosphorylation site for protein kinase C but do not support a role of this modification as a signal for TR endocytosis and recycling.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=553687Documentos Relacionados
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