CD98 at the crossroads of adaptive immunity and cancer, 2012
- Adaptive immunity, a vertebrate specialization, adds memory and exquisite specificity to the basic innate immune responses present in invertebrates while conserving metabolic resources. In adaptive immunity, antigenic challenge requires extremely rapid proliferation of rare antigen-specific lymphocytes to produce large, clonally expanded effector populations that neutralize pathogens. Rapid proliferation and resulting clonal expansion are dependent on CD98, a protein whose well-conserved orthologs appear restricted to vertebrates. Thus, CD98 supports lymphocyte clonal expansion to enable protective adaptive immunity, an advantage that could account for the presence of CD98 in vertebrates. CD98 supports lymphocyte clonal expansion by amplifying integrin signals that enable proliferation and prevent apoptosis. These integrin-dependent signals can also provoke cancer development and invasion, anchorage-independence and the rapid proliferation of tumor cells. CD98 is highly expressed in many cancers and contributes to formation of tumors in experimental models. Strikingly, vertebrates, which possess highly conserved CD98 proteins, CD98-binding integrins and adaptive immunity, also display propensity towards invasive and metastatic tumors. In this Commentary, we review the roles of CD98 in lymphocyte biology and cancer. We suggest that the CD98 amplification of integrin signaling in adaptive immunity provides survival benefits to vertebrates, which, in turn, bear the price of increased susceptibility to cancer.
4F2 cell-surface antigen heavy chain is a protein that in humans is encoded by the SLC3A2 (solute carrier family 3 member 2) gene.
SLC3A2 comprises the light subunit of the large neutral amino acid transporter (LAT1) that is also known as CD98 (cluster of differentiation 98)
LAT1 is a heterodimeric membrane transport protein that preferentially transports neutral branched (valine, leucine, isoleucine) and aromatic (tryptophan, tyrosine) amino acids. LAT is highly expressed in brain capillaries (which form the blood brain barrier) relative to other tissues.
A functional LAT1 transporter is composed of two proteins encoded by two distinct genes:
4F2hc/CD98 heavy subunit protein encoded by the SLC3A2 gene (this gene)
CD98 light subunit protein encoded by the SLC7A5 gene
A short protein description with the molecular wheight, isoforms, etc...
Use, when available, the link to Wikipedia (Es Trypsin)
External links not available on Wikipedia have to be added here
Wikigenes includes links to
- NCBI Gene
- NCBI SNP
- iHOP resource
CHEMICAL STRUCTURE AND IMAGES
When relevant for the function
- Primary structure
- Secondary structure
- Tertiary structure
- Quaternary structure
Protein Aminoacids Percentage
The Protein Aminoacids Percentage gives useful information on the local environment and the metabolic status of the cell (starvation, lack of essential AA, hypoxia)
Protein Aminoacids Percentage (Width 700 px)
SYNTHESIS AND TURNOVER
- Cell signaling and Ligand transport
- Structural proteins