SLC4A1AP (solute carrier family 4 member 1 adaptor protein), also known as kanadaptin, is a multifunctional nucleocytoplasmic shuttling protein with roles in cell signaling and protein adaptation. Primary function: SLC4A1AP localizes to both the nucleus and mitochondria 1, with a functional nuclear localization sequence recognized by importin-alpha/beta for nuclear import 2. The protein contains a forkhead-associated (FHA) domain that recognizes phosphopeptides, suggesting involvement in phosphorylation-mediated signaling pathways 3. Originally identified as a binding partner for kidney anion exchanger 1 (kAE1), human SLC4A1AP does not functionally interact with kAE1 in transfected cells and does not affect its trafficking 4. Mechanism: SLC4A1AP exhibits nuclear export activity and is highly expressed in tissues lacking kAE1, indicating broader cellular roles beyond anion exchanger adaptation 1. Disease relevance: A missense variant (rs9678851) in SLC4A1AP is genome-wide significantly associated with blood pressure regulation, identified through meta-analyses of 475,000 individuals 5. Additionally, SLC4A1AP alterations correlate with survival outcomes in laryngopharyngeal cancers with perineural/angiolymphatic invasion 6. Clinical significance: SLC4A1AP demonstrates stable gene expression in non-cancerous kidney biopsies, making it suitable as a reference gene for normalization in qPCR studies 7.