Transmembrane BAX inhibitor motif-containing protein 4 (TMBIM4)

Transmembrane BAX inhibitor motif-containing protein 4 (TMBIM4), also known as Golgi anti-apoptotic protein (GAAP) or Lifeguard 4, is a highly conserved multi-transmembrane protein broadly expressed in eukaryotic cells. TMBIM4 functions as a negative regulator of both intrinsic and extrinsic apoptotic pathways through its roles in maintaining intracellular calcium homeostasis, particularly in the Golgi apparatus and endoplasmic reticulum. It acts as a Golgi cation channel, decreasing Ca²⁺ release to attenuate triggers of cell death and promoting cell survival. TMBIM4 is also involved in cell adhesion, migration, and host-pathogen interactions. Dysregulation of TMBIM4 has been implicated in cancer, infection, and possibly other diseases involving aberrant apoptosis or calcium signaling[1][2][3][4].

Other names

Golgi anti-apoptotic protein (GAAP)Lifeguard 4 (LFG4)S1RZPROCGI-119Z-protein

Anti-apoptotic: Modulation of intracellular Ca²⁺ homeostasis, suppressing both intrinsic and extrinsic apoptosis by reducing Ca²⁺ release from stores and attenuating store-operated Ca²⁺ entry[1][2][3]. Inhibition of caspase-8 activation (through suppression of extrinsic apoptotic pathways)[2]. Direct modulation of cell death and Ca²⁺ signaling via interaction with Bcl-2 and Bcl-XL family proteins[2].