C2CD2 is a calcium-dependent lipid transporter localized to the endoplasmic reticulum (ER) that functions at ER-plasma membrane (PM) junctions. As a phospholipid transporter containing a C2 domain, C2CD2 mediates non-vesicular lipid transfer between the ER and PM 1. The protein forms complexes with band 4.1 family members and cell adhesion molecules like SynCAM 1, enriching ER-PM junctions at cell-cell contact sites 2. Unlike its brain-enriched paralog TMEM24, C2CD2 displays lower sensitivity to calcium-induced dissociation from the PM, suggesting tissue-specific regulatory properties 1. C2CD2-containing ER-PM junctions may participate in adaptive responses to cell contact-dependent signaling, particularly relevant in neurons where these structures are abundant 2. Genome-wide association studies have implicated C2CD2 variants in diverse phenotypes including hand grip strength, gait speed in older adults, childhood obesity through DNA methylation-mediated mechanisms, and gut microbiota composition, though effect sizes are small and replication has been inconsistent 3456. A C2CD2-TFF1 in-frame fusion transcript was identified in breast cancer 7. These findings suggest C2CD2 participates in fundamental cellular functions with modest contributions to complex traits.