CHMP1B is a peripheral component of the ESCRT-III complex that catalyzes membrane scission events across diverse cellular processes. The protein functions through a sequential polymerization mechanism, first forming single-stranded helical filaments that create moderate-curvature membrane tubules, followed by recruitment of IST1 to form a second strand that further constricts membranes nearly to the fission point 1. CHMP1B-IST1 complexes can sever membranes through a friction-driven mechanism independent of VPS4 and spastin 2. The protein is dynamically regulated by ubiquitination, with USP8 deubiquitinating CHMP1B in response to EGF stimulation, which is necessary for proper EGF receptor trafficking 3. CHMP1B plays specialized roles in Rab11a-positive recycling endosomes for exosome formation, distinct from its role in degradative pathways 4. Disease relevance includes involvement in Noonan syndrome bleeding disorders through dysregulated VEGFR2 signaling when LZTR1-mediated CHMP1B ubiquitination is disrupted 5. The protein is also hijacked by viral pathogens like CSFV to promote mitophagy through phagophore closure 6 and shows altered expression in Menière's disease 7.