Structure and function of molecular chaperones


Structure and function of molecular chaperones

Most of the cellular processes are executed by sets of proteins that work like molecular machines in a coordinated manner, thus acting like an assembly line and making the process a more efficient one. One of such assembly lines is the one formed by molecular chaperones, a group of proteins involved in cell homeostasis through two opposite functions, protein folding and degradation. Over the last years it has been found that chaperones are not only devoted to assisting the folding of other proteins, but also given the right conditions and the presence, they can be active players in protein degradation. The two processes are carried out through the transient formation of complexes between different chaperones and co-chaperones. Our goal is the structural characterization of some of these complexes, using as a main tool electron microscopy and image processing techniques, and combining the information obtained with the available atomic structures of some of these chaperones and co-chaperones, with the aim of understanding the structural mechanisms by which these complexes function. Another objective is to characterize, for some of these chaperones, the forces involved in their activity, using the novel technique of optical tweezers.


Structural characterisation of the centrosome and centrosomal proteins

The centrosome is the major microtubule organising center (MTOC) in most animal cells. Typically, centrosomes are made of a pair of centrioles embedded in what classical electron-microscopy (EM) studies defined as "electron-dense" amorphous, pericentriolar material (PCM). Until now, not much structural information has been obtained, mostly because of the size and complexity of this organelle. We plan to study the overall structure of the centrosome using two approaches. The first one is electron tomography, a technique that has recently undergone major advances, and which may allow the structural characterization of entire centrosomes in condition close to the native state. The second approach is to use X-ray tomography, a technique which certainly allows the reconstruction of whole centrosomes, albeit at lower resolution than electron tomography. We plan to use the facilities set up at the dedicated beam line of the Spanish ALBA Synchrotron.


José María Valpuesta

Jaime Martín-Benito



Post-doctoral investigators

Jorge Cuéllar

Rocio Arranz


Predoctoral students

Lucia Quintana

Marta Ukleja





Selected Publications


- J.A. Morín, Francisco J. Cao, J.M. Lázaro, J.R. Arias-Gonzalez, J. M. Valpuesta, J. L. Carrascosa, M. Salas and B. Ibarra. (2012)Active DNA unwinding dynamics of a processive DNA polymerase”. PNAS USA 109, 8115-8220.
- R. Arranz, G. Mercado, J. Martín-Benito, R. Giraldo, O. Monasterio, R. Lagos and J. M. Valpuesta (2012) “Structural characterization of microcin E492 amyloid formation: Identification of the precursors”J. Struct. Biol. 178, 54–60.
- A. Peña, K. Gewartowski, S. Mroczek, J. Cuéllar, A. Szykowska, A. Prokop, M. Czarnocki-Cieciura, J. Piwowarski, C. Tous, A. Aguilera, J. L. Carrascosa, J. M. Valpuesta* and A. Dziembowski* (2012) “Structural and biochemical characterisation of the THO complex reveals its architecture and mechanism of nucleic acids recognition” EMBO J.31, 1605-1616.


- H. Yébenes, P. Mesa, I. G. Muñoz, G. Montoya and J. M. Valpuesta (2011) “Chaperonins: two rings for folding” Trends Bio. Sci. 6, 424-32. (cover of the issue).
- I. G. Muñoz^, H. Yébenes^, M. Zhou, P. Mesa, M. Serna, A.Y. Park, E. Bragado-Nilsson, A. Beloso, G. de Cárcer, M. Malumbres, C. V. Robinson, J. M. Valpuesta* and G. Montoya* “Crystal structure of the mammalian cytosolic chaperonin CCT in complex with tubulin” (2011) Nat. Struct. Mol. Biol. 18, 14-9 (selected by the “Faculty of 1000”).


- Ramos, I., Martin-Benito, J., Finn, R., Bretaña, L., Aloria, K., Arizmendi, J.M., Ausió, J., A. Muga, Valpuesta, J.M.* and Prado, A* (2010) “Nucleoplasmin binds histone H2A-H2B dimers through its distal face” J. Biol. Chem. 285, 33771-33778.
- M. Moreno-del Álamo, A. Sánchez-Gorostiaga, A. M. Serrano, A. Prieto, J. Cuéllar, J. Martín-Benito, J. M. Valpuesta and R. Giraldo (2010) “The ISM Motif is the Main Target for Hsp70 Chaperones in the AAA+ Domain of Yeast Orc4p and Modulates Essential Interactions with Orc2p” J. Mol. Biol. 403, 24-39.


- C. Reiriz, R. J. Brea, R. Arranz, J. L. Carrascosa, A. Garibotti, B. Manning, J. M. Valpuesta, and J. R. Granja. “α,γ-Peptide Nanotube Templating 1D Parallel Fullerene Arrangements”.  J. Am. Chem. Soc. 131, 11335–11337. (2009)
- S. Hormeño, B. Ibarra, F. J. Chichón, K. Habermann, B. M. H. Lange, J. M. Valpuesta, J. L. Carrascosa y J. R. Arias-Gonzalez.  “Single centrosome manipulation reveals its electric charge and associated dynamic structure” Biophysical J. 97,1022-30. (2009)
- M. Alvarado-Kristensson, M. J. Rodríguez, V. Silió, J. M. Valpuesta  and A. C. Carrera. “SADB kinases mediated gamma-tubulin phosporylation regulates centrosome duplication” Nat. Cell. Biol. 11, 1081-92. (2009) (selected by the “Faculty of 1000”).


- J. Cuéllar, J. Martín-Benito, S. H.W. Scheres, R. Sousa, F. Moro, E. López-Viñas, P. Gómez-Puertas, A. Muga, J. L. Carrascosa and J. M. Valpuesta. “The structure of a CCT:Hsc70NBD complex suggests a mechanism for Hsp70 delivery of substrates to the chaperonin”  Nat. Struct. Mol. Biol. 15, 858-864. (2008) (selected by the “Faculty of 1000”).
- J. P. Schuermann, J. Jiang, J. Cuéllar, O. Llorca, L. Wang, A. B. Taylor, B. Demeler, K. Morano, P. John Hart, J. M. Valpuesta, E. M. Lafer and Rui Sousa. “Structure of the Hsp110:Hsc70 Nucleotide Exchange Complex” Mol. Cell 31, 232-243. (2008) (selected by the “Faculty of 1000”).


- J. Martín-Benito, J. Grantham, J. Boskovic, K. I. Brackley, J. L. Carrascosa, K. R. Willison and J. M. Valpuesta. “The inter-ring arrangement of the cytosolic chaperonin CCT” EMBO reports 8, 252-257. (2007)
- J. Martín-Benito, J. Gómez-Reino, P. C. Stirling, V. F. Lundin, P. Gómez-Puertas, J. Boskovic, P. Chacón, J. J. Fernández, J. Berenguer, M. R. Leroux and J. M. Valpuesta. “Divergent substrate-binding mechanisms reveal an evolutionary specialization of eukaryotic prefoldin compared to its archaeal counterpart” Structure 15, 101-110. (2007) (cover of the issue).


– O. Llorca, M. Betti, J. M. González, A. Valencia, A. J. Márquez and J. M. Valpuesta. “The three-dimensional structure of an eukaryotic glutamine synthetase. Functional implications of its oligomeric structure”. J. Struct. Biol. 156, 469-479. (2006)


- X. Agirrezabala, J. Martín-Benito, J. R. Castón, R. Miranda, J. M. Valpuesta  and José L. Carrascosa. “Maturation of phage T7 capsid involves structural modification of both the shell and the inner core components” EMBO J. 24, 3820-3829. (2005)
- W.A. Schamel, I. Arechaga, R. M. Risueño, P. Cabezas, C. Risco, J. M. Valpuesta and B. Alarcón. “High sensitivity and poor saturability of response is explained by the co-existence of monovalent and multivalent t cell antigen receptor complexes” J. Exp.Med. 202, 493-503. (2005) (selected by the “Faculty of 1000”).
- S. Bertrand, I. Barthelemy, M. A. Oliva, J. L. Carrascosa, J. M. Andreu  and J. M. Valpuesta. “Folding, stability and polymerization properties of FtsZ chimeras with inserted tubulin loops involved in the interaction with the cytosolic chaperonin CCT and in microtubule formation” J. Mol. Biol. 346, 319-330. (2005)


- J. Martín-Benito, S. Bertrand, T. Hu, P. J. Ludtke, J. N. McLaughlin, B. M. Willardson, J. L. Carrascosa and J. M. Valpuesta. “Structure of the complex between the cytosolic chaperonin CCT and phosducin-like protein” PNAS USA 101, 17410-17415. (2004)
- V. F. Lundin, P. C. Stirling, J. Gomez-Reino, P. B. Kim, J. C. Mwenifumbo, J. M. Obst, J. M. Valpuesta and M. R. Leroux. “Molecular clamp mechanism of substrate binding by hydrophobic coiled coil residues in the archaeal chaperone, prefoldin” PNAS USA  101, 4367-4372. (2004) (selected by the “Faculty of 1000”).


- J. Martín-Benito, J. Boskovic, P. Gómez-Puertas, J. L. Carrascosa, C. Simons, S. A. Lewis, F. Bartolini, N. J. Cowan  and J. M. Valpuesta.” Structure of eukaryotic prefoldin and of its complexes with unfolded actin and the cytosolic chaperonin CCT”. EMBO J. 21, 6377-6386. (2002) 
- J.M. Valpuesta, J. Martín-Benito, P. Gómez-Puertas, J.L. Carrascosa and K. R. Willison. (2002) “Structure and function of a protein folding machine: the eukaryotic cytosolic chaperonin CCT” FEBS lett. 529, 11-16. (2002)
- M.H.K. Ebbing, M.J. Villa, J.M. Valpuesta, P. Prados and J. de Mendoza. “Resorcinarenes with 2-benzimidazolone bridges: self-aggregation, self-assembled dimeric capsules, and guest encapsulation” PNAS USA 99, 4962-4966. (2002)


- O. Llorca, J. Martín-Benito, J. Grantham, M. Ritco-Vonsovici, K. R. Willison, J. L. Carrascosa and J. M. Valpuesta. “The “sequential allosteric ring” mechanism in the eukaryotic chaperonin-assisted folding of actin and tubulin” EMBO J. 20, 4065-4075. (2001) (cover of the issue).
- O. Llorca, J. Martín-Benito, P. Gómez-Puertas, M. Ritco-Vonsovici, K. R. Willison, J. L. Carrascosa and J. M. Valpuesta. “Analysis of the interaction between the eukaryotic chaperonin CCT and its substrates actin and tubulin” J. Struct. Biol. 135, 205-218. (2001)
- J.M. Valpuesta and J.L. Carrascosa. “Chaperonins: folding in the hole” J. Struct. Biol. 135, 83. (2001)


- O. Llorca, J. Martín-Benito, M. Ritco-Vonsovici, J. Grantham, K. R. Willison, J. L. Carrascosa and J. M. Valpuesta. "Eukaryotic chaperonin CCT stabilizes actin and tubulin folding intermediates in open quasi-native conformations" EMBO J. 19, 5971-5979. (2000) (cover of the issue).
- J.M. Valpuesta, N. Sousa, I. Barthelemy, J.J. Fernández, H. Fujisawa, B. Ibarra  and J.L. Carrascosa. “Structural analysis of the bacteriophage T3 head-to-tail connector” J. Struct. Biol. 131, 146-155. (2000)  (cover of the issue).


- O. Llorca, E. McCormack, G. Hynes, J. Grantham, J. Cordell, J. L. Carrascosa, K. R. Willison, J. J. Fernández  and J. M. Valpuesta. “Eukaryotic type II chaperonin CCT interacts with actin through specific subunits” Nature 402, 693-696. (1999)
- O. Llorca, M. G. Smyth, J. L. Carrascosa, K. R.Willison, M. Radermacher, S. Steinbacher  and J. M. Valpuesta. “3D reconstruction of the ATP-bound form of CCT reveals the asymmetric folding conformation of a type II chaperonin” Nat. Struct. Biol. 6, 639-642. (1999)
- J.M. Valpuesta, J. J. Fernández, J.M. Carazo and J. L. Carrascosa. "The three-dimensional structure of a DNA translocating machine at 10 Å resolution" Structure 7, 289-296. (1999)



Active Funding

2013-2015. Mutua Madrileña Foundation “Caracterización estructural de la proteína asociada al cáncer de mama, BRCA1, e identificación de dianas moleculares susceptibles de bloquear el desarrollo del proceso oncológico”.

2011-2013. UE 262943-2 “MULTIFUN. Multifunctional Nanotechnology for selective detection and Treatment of Cancer”.

2011-2013. SEPAR Foundation “Ultraestructura de los complejos lipoproteicos del sistema surfactante pulmonar”.

2011-2013. MICINN BFU2010-15703/BMC. “Chaperonas moleculares: una cadena de montaje involucrada en el plegamiento y degradacion de proteinas.

-2010-2013. CAM (S2009MAT-1507) “NOBIMAT-M. Nuevos materiales y dispositivos biofuncionales híbridos en Nanociencia”.


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