CD98 constitutes the heavy chain of the heterodimeric complex and is required for the surface expression and basolateral localization of the amino acid transporter complex in polarized epithelial cells. The CD98 heavy chain also interacts with beta 1 integrins and regulates their activation through the cytoplasmic domains and transmembrane regions. Studies suggest that overexpression of CD98 may contribute to cell growth and survival by regulating integrin signalling, and therefore may play an important role in tumorigenesis.
