The function of FBXL4 (F-box and leucine rich repeat protein 4, Ensembl gene identifier ENSG00000112234) is as follows. Substrate-recognition component of the mitochondria-localized SCF-FBXL4 ubiquitin E3 ligase complex that plays a role in the restriction of mitophagy by controlling the degradation of BNIP3 and NIX mitophagy receptors (PubMed:36896912, PubMed:38992176). Rescues also mitochondrial injury through reverting hyperactivation of DRP1- mediated mitochondrial fission (By similarity). {ECO:0000250|UniProtKB:Q8BH70, ECO:0000269|PubMed:36896912, ECO:0000269|PubMed:38992176}.