TM4SF1 and infection: To understand the significance of the respective C-termini in modulating cellular functions, mutants in which the C-terminus was deleted (i.e., ΔC) or chimeric proteins in which the C-terminus was replaced with that from another protein (i.e., 1C5 denotes the chimera in which the C-terminus of TM4SF1 was replaced with the counterpart from TM4SF5) (Figure 1B) were constructed for stable infections.