title: Interaction of a putative BH3 domain of clusterin with anti-apoptotic Bcl-2 family proteins as revealed by NMR spectroscopy.
abstract: Clusterin (CLU) is a multifunctional glycoprotein that is overexpressed in prostate and breast cancers. Although CLU is known to be involved in the regulation of apoptosis and cell survival, the precise molecular mechanism underlying the pro-apoptotic function of nuclear CLU (nCLU) remains unclear. In this study, we identified a conserved BH3 motif in C-terminal coiled coil (CC2) region of nCLU by sequence analysis and characterized the molecular interaction of the putative nCLU BH3 domain with anti-apoptotic Bcl-2 family proteins by nuclear magnetic resonance (NMR) spectroscopy. The chemical shift perturbation data demonstrated that the nCLU BH3 domain binds to pro-apoptotic BH3 peptide-binding grooves in both Bcl-X(L) and Bcl-2. A structural model of the Bcl-X(L)/nCLU BH3 peptide complex reveals that the binding mode is remarkably similar to those of other Bcl-X(L)/BH3 peptide complexes. In addition, mutational analysis confirmed that Leu323 and Asp328 of nCLU BH3 domain, absolutely conserved in the BH3 motifs of BH3-only protein family, are critical for binding to Bcl-X(L). Taken altogether, our results suggest a molecular basis for the pro-apoptotic function of nCLU by elucidating the residue specific interactions of the BH3 motif in nCLU with anti-apoptotic Bcl-2 family proteins.
authors.affiliation: Medical Proteomics Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea.
authors.forename: Dong-Hwa
authors.initials: DH
authors.lastname: Lee
authors.forename: Ji-Hyang
authors.initials: JH
authors.lastname: Ha
authors.forename: Yul
authors.initials: Y
authors.lastname: Kim
authors.forename: Kwang-Hee
authors.initials: KH
authors.lastname: Bae
authors.forename: Jae-Yong
authors.initials: JY
authors.lastname: Park
authors.forename: Wan Sung
authors.initials: WS
authors.lastname: Choi
authors.forename: Ho Sup
authors.initials: HS
authors.lastname: Yoon
authors.forename: Sung Goo
authors.initials: SG
authors.lastname: Park
authors.forename: Byoung Chul
authors.initials: BC
authors.lastname: Park
authors.forename: Gwan-Su
authors.initials: GS
authors.lastname: Yi
authors.forename: Seung-Wook
authors.initials: SW
authors.lastname: Chi
mesh_terms: D000595:Amino Acid Sequence; D017209:Apoptosis; D001224:Aspartic Acid / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D051152:Clusterin / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D007930:Leucine / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D017434:Protein Structure, Tertiary / Q000235:genetics; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D051152:Clusterin; D019253:Proto-Oncogene Proteins c-bcl-2; D001224:Aspartic Acid; D007930:Leucine