Updated publication reference for PubMed record(s): 32973183. We used immunoprecipitation (IP) and mass spectrometry (MS) to identify proteins that interact with MFSD7C. Because an anti-MFSD7C monoclonal antibody is not available, we used MFSD7C tagged with both Myc and FLAG epitopes in a MFSD7C-expressing murine alveolar macrophage cell line MH-S (Supplementary Fig. 2a-c and see Methods for details). A total of 58 proteins were identified excluding MFSD7C and common contaminants of IP experiments such as keratin, actin, and ribosomal proteins (Table 1). Twenty-six of the 58 proteins are annotated as mitochondrial proteins and 4 (three Fc receptors and one integrin) are known to reside in the cytoplasmic membrane. The 58 proteins were classified into 10 different functional categories based on gene ontology.