PIK3CG and influenza: In summary, the Ras–PI3K interaction, identified here as a host-oriented mechanism for influenza internalization, is implicated in very specific cellular phenomena, including clathrin-independent endocytosis and endosomal maturation, and is separate from clathrin-dependent endocytosis, which is necessary for a number of important biological events, such as receptor downregulation and low-density lipoprotein incorporation.