Midbody Targeting of the ESCRT Machinery by a Noncanonical Coiled Coil in CEP55

The ESCRT (endosomal sorting complex required for transport) machinery is required for the scission of membrane necks in processes including the budding of HIV-1 and cytokinesis. An essential step in cytokinesis is recruitment of the ESCRT-I complex and the ESCRT-associated protein ALIX to the midbody (the structure that tethers two daughter cells) by the protein CEP55. Biochemical experiments show that peptides from ALIX and the ESCRT-I subunit TSG101 compete for binding to the ESCRT and ALIX-binding region (EABR) of CEP55. We solved the crystal structure of EABR bound to an ALIX peptide at a resolution of 2.0 angstroms. The structure shows that EABR forms an aberrant dimeric parallel coiled coil. Bulky and charged residues at the interface of the two central heptad repeats create asymmetry and a single binding site for an ALIX or TSG101 peptide. Both ALIX and ESCRT-I are required for cytokinesis, which suggests that multiple CEP55 dimers are required for function.

[1]  G. Fang,et al.  Cep55, a microtubule-bundling protein, associates with centralspindlin to control the midbody integrity and cell abscission during cytokinesis. , 2006, Molecular biology of the cell.

[2]  R. D. Fisher,et al.  ALIX-CHMP4 interactions in the human ESCRT pathway , 2008, Proceedings of the National Academy of Sciences.

[3]  R. D. Fisher,et al.  Structural and Biochemical Studies of ALIX/AIP1 and Its Role in Retrovirus Budding , 2007, Cell.

[4]  G. Gould,et al.  Breaking up is hard to do – membrane traffic in cytokinesis , 2008, Journal of Cell Science.

[5]  P. Hanson,et al.  Plasma membrane deformation by circular arrays of ESCRT-III protein filaments , 2008, The Journal of cell biology.

[6]  S. Gygi,et al.  Human ESCRT and ALIX proteins interact with proteins of the midbody and function in cytokinesis , 2007, The EMBO journal.

[7]  H. Stenmark,et al.  Endosomal and non-endosomal functions of ESCRT proteins. , 2006, Trends in cell biology.

[8]  F. Barr,et al.  Cytokinesis: Placing and Making the Final Cut , 2007, Cell.

[9]  H. Gerdes,et al.  The novel centrosomal associated protein CEP55 is present in the spindle midzone and the midbody. , 2006, Genomics.

[10]  M. Glotzer,et al.  The Molecular Requirements for Cytokinesis , 2005, Science.

[11]  K. Khanna,et al.  Cdk1/Erk2- and Plk1-dependent phosphorylation of a centrosome protein, Cep55, is required for its recruitment to midbody and cytokinesis. , 2005, Developmental cell.

[12]  R. D. Fisher,et al.  Structural and functional studies of ALIX interactions with YPXnL late domains of HIV-1 and EIAV , 2008, Nature Structural &Molecular Biology.

[13]  M. Russell,et al.  A concentric circle model of multivesicular body cargo sorting , 2007, EMBO reports.

[14]  P. S. Kim,et al.  X-ray structure of the GCN4 leucine zipper, a two-stranded, parallel coiled coil. , 1991, Science.

[15]  J. Hurley,et al.  Beyond Tsg101: the role of Alix in 'ESCRTing' HIV-1 , 2007, Nature Reviews Microbiology.

[16]  P. Bieniasz,et al.  Late budding domains and host proteins in enveloped virus release. , 2006, Virology.

[17]  J. Hurley,et al.  ESCRT complexes and the biogenesis of multivesicular bodies. , 2008, Current opinion in cell biology.

[18]  K. Nagashima,et al.  An Alix Fragment Potently Inhibits HIV-1 Budding , 2006, Journal of Biological Chemistry.

[19]  J. Martin-Serrano,et al.  Differential requirements for Alix and ESCRT-III in cytokinesis and HIV-1 release , 2008, Proceedings of the National Academy of Sciences.

[20]  J. Hurley,et al.  Molecular Architecture and Functional Model of the Complete Yeast ESCRT-I Heterotetramer , 2007, Cell.

[21]  A. Lupas,et al.  Predicting coiled coils from protein sequences , 1991, Science.

[22]  S. Emr,et al.  ESCRTing proteins in the endocytic pathway. , 2007, Trends in biochemical sciences.

[23]  Wesley I. Sundquist,et al.  Structure of the Tsg101 UEV domain in complex with the PTAP motif of the HIV-1 p6 protein , 2002, Nature Structural Biology.

[24]  J. Martin-Serrano,et al.  Parallels Between Cytokinesis and Retroviral Budding: A Role for the ESCRT Machinery , 2007, Science.

[25]  J. Hurley,et al.  Structural basis for endosomal targeting by the Bro1 domain. , 2005, Developmental cell.

[26]  Roger L. Williams,et al.  The emerging shape of the ESCRT machinery , 2007, Nature Reviews Molecular Cell Biology.

[27]  W. Weissenhorn,et al.  The Crystal Structure of the C‐Terminal Domain of Vps28 Reveals a Conserved Surface Required for Vps20 Recruitment , 2006, Traffic.