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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
10
pubmed:dateCreated
1999-12-2
pubmed:abstractText
The invariant chain (Ii) plays a critical role in the transport of newly synthesized class II molecules to endosomal Ag-processing compartments. Of the two major isoforms of human Ii, only Ii-p35 is phosphorylated in vivo, and inhibiting Ii phosphorylation inhibits the trafficking of newly synthesized class II molecules to Ag-processing compartments. We now report that a member of the protein kinase C family of serine/threonine kinases is responsible for the constitutive phosphorylation of 50% of the total cellular pool of Ii-p35 in a wide variety of APCs, including B lymphocytes, PBMC, immature dendritic cells, and mature dendritic cells. Stimulation of protein kinase C activity in APCs significantly enhanced the kinetics of degradation of class II-associated Ii in Ag-processing compartments and the binding of antigenic peptides to these class II molecules. In cells expressing an Ii-phosphorylation mutant, trafficking of class II molecules to endosomes was impaired and Ii proteolysis was inhibited, demonstrating a direct effect of Ii phosphorylation on MHC class II trafficking. These results demonstrate that phosphorylation of Ii in APCs alters the kinetics of trafficking of newly synthesized class II molecules to lysosomal Ag-processing compartments.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0022-1767
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
163
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
5435-43
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
Phosphorylation of the invariant chain by protein kinase C regulates MHC class II trafficking to antigen-processing compartments.
pubmed:affiliation
Experimental Immunology Branch, National Cancer Institute, Bethesda, MD 20892, USA.
pubmed:publicationType
Journal Article