Regarding cell surface expression of hCAT-1, it has been determined that activation of protein kinase C (PKC) reduces cell surface expression of hCAT-1 and L-arginine transport in Xenopus laevis oocytes and U373MG glioblastoma cells (Rotmann et al., 2004a,b), reinforcing the idea that a rapid mobilization of hCAT-1 from plasma membrane to cytoplasm reduces L-arginine transport. This evidence concerns the gene SLC7A1 and glioblastoma.