Abstract
Lectin-like transcript 1 (LLT1) encoded by CLEC2D gene is a C-type lectin-like molecule interacting with human CD161 (NKR-P1A) receptor expressed by natural killer cells and subsets of T cells. Using RT-PCR and sequencing, we identified several CLEC2D alternatively spliced transcript variants generated by exon skipping. In addition to the reported transcript variants 1 (LLT1) and 2, we identified a novel splice variant 4 and transcripts coding for putative soluble proteins. CLEC2D transcripts were detected primarily in hematopoietic cell lines and were found to be co-induced by the same activation signals. Although very low amounts of putative soluble CLEC2D protein isoforms could be produced by transfectants, CLEC2D isoforms 2 and 4 were efficiently expressed. By contrast to LLT1, which was detected on the cell surface, isoform 2 and 4 remained in the endoplasmic reticulum where they formed homodimers or heterodimers with LLT1. They failed to interact with CD161, leaving LLT1 as the sole ligand for this receptor. CLEC2D therefore uses gene splicing to generate protein isoforms that are structurally distinct and that have different biological activities.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Alternative Splicing*
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Amino Acid Sequence
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Animals
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Base Sequence
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Blotting, Western
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Cell Line, Tumor
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Cells, Cultured
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Endoplasmic Reticulum / metabolism
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Gene Expression Profiling
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HEK293 Cells
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Humans
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Jurkat Cells
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Lectins, C-Type / chemistry
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Lectins, C-Type / genetics*
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Lectins, C-Type / metabolism
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Mice
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Models, Molecular
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Molecular Sequence Data
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NK Cell Lectin-Like Receptor Subfamily B / chemistry
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NK Cell Lectin-Like Receptor Subfamily B / genetics
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NK Cell Lectin-Like Receptor Subfamily B / metabolism
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Protein Binding
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Protein Isoforms / chemistry
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Protein Isoforms / genetics
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Protein Isoforms / metabolism
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Protein Multimerization
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RNA, Messenger / genetics
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RNA, Messenger / metabolism
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Receptors, Cell Surface / chemistry
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Receptors, Cell Surface / genetics*
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Receptors, Cell Surface / metabolism
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Reverse Transcriptase Polymerase Chain Reaction
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Sequence Homology, Amino Acid
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Sequence Homology, Nucleic Acid
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Transcription, Genetic / genetics*
Substances
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CLEC2D protein, human
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KLRB1 protein, human
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Lectins, C-Type
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NK Cell Lectin-Like Receptor Subfamily B
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Protein Isoforms
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RNA, Messenger
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Receptors, Cell Surface