TMBIM4 (transmembrane BAX inhibitor motif containing 4), also known as GAAP (Golgi anti-apoptotic protein), is a ubiquitously expressed 1, multi-transmembrane cation-selective ion channel 2 with primary functions in apoptosis inhibition and calcium homeostasis. TMBIM4 localizes to both the Golgi apparatus and endoplasmic reticulum 1, and more recently to the plasma membrane 3. It regulates intracellular Ca2+ fluxes through store-operated entry and IP3-mediated release 2, reduces endoplasmic reticulum Ca2+ content 1, and confers resistance to diverse apoptotic stimuli 2. Functionally, TMBIM4 enhances cell migration and invasion through focal adhesion turnover 4 and promotes hydrogen peroxide accumulation affecting cell invasiveness 4. Developmentally, TMBIM4 controls left-right patterning during gastrulation by regulating pluripotency exit through membrane potential maintenance 3. Disease relevance includes congenital heart disease with cardiac heterotaxy from TMBIM4 variants 3, preeclampsia where TMBIM4 deficiency facilitates NLRP3 inflammasome-induced trophoblast pyroptosis 5, age-related cataracts where miR-125a-3p suppression of TMBIM4 increases lens epithelial cell apoptosis 6, and hypertension susceptibility in African-ancestry populations 7. These findings establish TMBIM4 as a multifunctional protein critical for cellular survival, developmental patterning, and disease prevention.