Absence of evidence that Slc12a8 encodes a nicotinamide mononucleotide transporter

Schmidt MS, Brenner C · Nature Metabolism

A formal rebuttal arguing that the reported Slc12a8 data do not establish a dedicated NMN transporter, and that the prevailing model — NMN dephosphorylated to nicotinamide riboside before cell entry — remains unrefuted.

Limitations

A correspondence item presenting argument and reanalysis rather than new experiments. The senior author has long-standing commercial involvement with nicotinamide riboside, the rival precursor.