CD98

CD98 (Cluster of Differentiation 98), also known as SLC3A2 (solute carrier family 3 member 2), is a protein that in humans is encoded by the SLC3A2 gene. CD98 plays a crucial role in amino acid transport and has been implicated in various physiological and pathological processes, including cell adhesion, nutrient uptake, and the regulation of cellular growth and differentiation. It is a type II membrane glycoprotein that forms heterodimers with various members of the L-type amino acid transporter (LAT) family, facilitating the transport of large neutral amino acids across cell membranes.

Structure and Function[edit | edit source]

CD98 consists of a heavy chain (CD98hc) and is non-covalently linked to light chains, which are members of the LAT family. The heavy chain is encoded by the SLC3A2 gene and is responsible for the interaction with integrins, contributing to cell adhesion and signaling. The light chains are responsible for amino acid transport. This heterodimerization is essential for the transport activity and the functional expression of the light chains at the cell surface.

Physiological Role[edit | edit source]

CD98 plays a significant role in various physiological processes. It is involved in the regulation of amino acid homeostasis, which is crucial for protein synthesis and cell growth. Additionally, CD98's interaction with integrins suggests a role in cell adhesion and migration, processes important in development, immune responses, and wound healing. Its expression is upregulated in rapidly dividing cells, including embryonic and cancer cells, highlighting its importance in cell proliferation.

Pathological Implications[edit | edit source]

Due to its role in cell growth and nutrient uptake, CD98 has been implicated in cancer biology. Its overexpression is observed in various types of cancers and is associated with tumor aggressiveness, poor prognosis, and resistance to therapy. Furthermore, CD98 is involved in the regulation of the immune response, and alterations in its expression or function can contribute to autoimmune diseases and inflammation.

Clinical Significance[edit | edit source]

Given its involvement in cancer and immune regulation, CD98 is a potential target for therapeutic intervention. Inhibiting CD98 function could limit tumor growth and metastasis by restricting nutrient uptake and disrupting cell adhesion and signaling pathways. Additionally, modulating CD98 activity could have therapeutic potential in autoimmune diseases and inflammatory conditions.

Research Directions[edit | edit source]

Current research is focused on understanding the detailed mechanisms of CD98 in amino acid transport, its interaction with integrins, and its role in pathological conditions. Developing specific inhibitors or modulators of CD98 could provide new therapeutic options for cancer and other diseases associated with its dysregulation.

File:Protein SLC3A2 PDB 1xr9.png

Crystal structure of a fragment of human CD98.