BID His Tag Protein, Human

BID (BH3 Interacting Domain Death Agonist) is a critical BH3-only pro-apoptotic protein containing an unstructured N-terminal domain and a conserved C-terminal BH3 domain. Upon cleavage by caspase-8, BID generates the active fragment tBID, which subsequently activates Bax/Bak and induces mitochondrial outer membrane permeabilization. Serving as an essential bridge between the death receptor and mitochondrial pathways, BID not only mediates apoptosis but also participates in hematopoietic homeostasis, tumor suppression, and mitochondrial structural maintenance. Aberrant BID expression is closely associated with various diseases: in tumors, its downregulation inhibits apoptosis and promotes drug resistance; during SARS-CoV-2 infection, the virus modulates BID to balance host cell survival and death; moreover, abnormal expression of BID alternative splicing isoforms is significantly correlated with the progression and poor prognosis of malignancies such as colorectal cancer, establishing BID as a potential diagnostic biomarker and therapeutic target.