Analysis of Nucleocytoplasmic Trafficking of the HuR Ligand APRIL and Its Influence on CD83 Expression

Autor: Cordula Grüttner, Barbara Fries, Carol Stocking, Ralph H. Kehlenbach, Joachim Hauber, Jochen Heukeshoven, Jan Chemnitz, Ilona Hauber
Rok vydání: 2007
Předmět:
Cytoplasm
T-Lymphocytes
Tumor Necrosis Factor Ligand Superfamily Member 13
Active Transport
Cell Nucleus
Immunoglobulins
chemical and pharmacologic phenomena
Protein Sorting Signals
Biology
Ligands
Biochemistry
Jurkat cells
ELAV-Like Protein 1
Jurkat Cells
Mice
03 medical and health sciences
Antigens
CD
RNA interference
Chlorocebus aethiops
Animals
Humans
RNA
Messenger
Phosphorylation
Nuclear export signal
Molecular Biology
030304 developmental biology
Cell Nucleus
Antigen Presentation
0303 health sciences
Messenger RNA
Membrane Glycoproteins
COS cells
030302 biochemistry & molecular biology
Intracellular Signaling Peptides and Proteins
Nuclear Proteins
RNA-Binding Proteins
hemic and immune systems
Translation (biology)
Dendritic Cells
Cell Biology
Molecular biology
ELAV Proteins
Gene Expression Regulation
Antigens
Surface
COS Cells
NIH 3T3 Cells
Nuclear transport
Protein Processing
Post-Translational
HeLa Cells
Zdroj: Journal of Biological Chemistry. 282:4504-4515
ISSN: 0021-9258
DOI: 10.1074/jbc.m608849200
Popis: Dendritic cells (DC) are the most potent antigen-presenting cells of the immune system and are able to sensitize even naïve T cells. Mature DC are characterized by expression of CD83, a surface molecule that is proposed to be involved in efficient T cell activation. It has been recently shown that CD83 mRNA is transported from the nucleus to the cytoplasm in a HuR- and CRM1-dependent manner. Therefore we here investigated the impact of two known protein ligands of HuR, pp32 and APRIL, on CD83 expression. Both pp32 (ANP32A) and APRIL (ANP32B) are shuttle proteins, and it has been reported earlier that these HuR ligands can act as adaptors that link HuR and the CRM1-specific nuclear export pathway. By employing RNA interference (RNAi) technology we demonstrate that pp32 is dispensable for CD83 expression, whereas APRIL contributes to the nuclear export and subsequent translation of CD83 mRNA. Furthermore, we have determined the nuclear import signal (NLS) as well as the nuclear export signal (NES) of human APRIL. Moreover, we analyzed the status of phosphorylation of endogenous APRIL and identified threonine 244 to be an as yet unrecognized phosphate acceptor. Finally, we were able to show that phosphorylation of this specific amino acid residue regulates the nuclear export of APRIL. In sum, we report here the signal sequences in APRIL that mediate its intracellular trafficking and provide evidence that this protein ligand of HuR is an important player in the post-transcriptional regulation of CD83 expression by affecting the nucleocytoplasmic translocation of CD83 mRNA.
Databáze: OpenAIRE
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