TY - JOUR T1 - Live cell kinetic analysis of the LMO2/LDB1 leukemogenic protein complex reveals a hierarchy of turnover with implications for complex assembly JF - bioRxiv DO - 10.1101/706259 SP - 706259 AU - Justin H. Layer AU - Michael Christy AU - Lindsay Placek AU - Derya Unutmaz AU - Yan Guo AU - Utpal P. Davé Y1 - 2019/01/01 UR - http://biorxiv.org/content/early/2019/07/21/706259.1.abstract N2 - Multisubunit protein complexes operate in many cellular functions. The LMO2/LDB1 macromolecular complex has been posited to be critical in hematopoietic stem and progenitor cell specification and in the development of acute leukemia. This complex is comprised of core subunits of LMO2 and LDB1 as well as bHLH and GATA transcription factors. We analyzed the steady state abundance and kinetic stability of LMO2 and its partners via Halo protein tagging in conjunction with variant proteins deficient in binding their respective direct protein partners. We discovered a hierarchy of protein stability, with half lives in descending order: LDB1>SSBP>LMO2>TAL1. Importantly, LDB1’s turnover was markedly prolonged and LDB1 conferred enhanced stability upon each and every subunit component thereby nucleating the formation of the multisubunit protein complex. Our studies provide significant insights into LMO2/LDB1 macromolecular protein complex assembly and stability, which has implications for understanding its role in blood cell formation and for therapeutically targeting this complex in human leukemias. ER -