Another member of the family, SLC35E1, was described as a protein relevant for the development of the herpes simplex type 1 virus (53), but this does not preclude transport activity for small molecules; there is another example of a transporter (NTCP) being important for the infection with hepatitis B virus and in parallel, being a transporter of several small molecular substances (54). Here, SLC35E1 is linked to infection.