Truncated BH3 interacting domain death agonist (tBID)

tBID (truncated BH3 interacting domain death agonist) is a pro-apoptotic member of the BCL-2 protein family produced by caspase-8–mediated cleavage of BID during activation of death receptors (such as Fas or TNFR1). Upon cleavage, tBID translocates to mitochondria, where it engages in multiple, overlapping pro-apoptotic mechanisms: it activates BAX and BAK, blocks pro-survival BCL-2 family members, and can itself directly permeabilize the mitochondrial membrane to initiate apoptosis[2][1]. This activity links extrinsic death receptor signals to the intrinsic mitochondrial apoptosis pathway, playing a key role in programmed cell death, immunity, infection, and cancer resistance to therapy[2][5][6]. Emerging evidence shows that tBID can act as a direct MOMP effector, a function previously assigned only to BAX, BAK, and BOK, revealing new therapeutic opportunities, particularly in cancers that evade BAX/BAK-mediated death[2][1][3]. The term "tBid induction" is technically a process (production or activation of tBID) rather than a specific protein or receptor, hence its use as a standalone target name is not strictly correct—adjust the canonical target to "truncated BH3 interacting domain death agonist (tBID)".

Other names

truncated BIDtruncated BH3-only protein BIDtBID proteinp15 BID

Direct permeabilization of the mitochondrial membrane (tBID itself can act as a pore-forming effector in some contexts) Binding and inhibition of anti-apoptotic BCL-2 family proteins (e.g., BCL-2, BCL-XL) Activation of pro-apoptotic effectors BAX and BAK, leading to apoptosis