- Review Article
- Published:
Ubiquitin and proteasomes
Protein regulation by monoubiquitin
Nature Reviews Molecular Cell Biologyvolume 2, pages195–201 (2001)Cite this article
10kAccesses
978Citations
6Altmetric
Key Points
Multi-ubiquitin chains target proteins for destruction by the proteasome. However, several proteins are monoubiquitylated. Recently, monoubiquitin has emerged as a regulator of the location and activity of diverse cellular proteins.
Histone regulation: Core histones H2A and H2B and the linker histone H1 are monoubiquitylated. Ubiquitylation of histones is important for gene expression during meiosis and development.
Endocytosis: Monoubiquitin serves as a signal to trigger the regulated internalization of plasma membrane proteins. Monoubiquitylation might also regulate the activity of components of the endocytic machinery.
Virus budding: The retrovirus Gag polyprotein is monoubiquitylated and this modification is required for late stages of virus budding from infected cells.
Surface regions of ubiquitin that are important for its different functions have been defined. One hydrophobic patch is promiscuous and is crucial for such diverse processes as proteasomal degradation and endocytosis. Another surface patch is important only for endocytosis and might have a role specifically in monoubiquitin functions.
Modification with monoubiquitin might regulate protein location and activity in ways that are similar to modification with the ubiquitin-like proteins, SUMO-1, Rub1 and Apg12.
Regulation of ubiquitin modification is important so that monoubiquitylated proteins are not inappropriately multi-ubiquitylated and degraded. Monoubiquitylation could be regulated by the activity of specific components of the ubiquitin machinery, by de-ubiquitylating enzymes, or by the presence or absence of positive and negative regulators of multi-ubiquitin chain assembly.
Many more monoubiquitin proteins probably exist and remain to be identified. The mechanism by which monoubiquitin regulates substrate protein location and activity is a mystery that is the next big challenge for researchers in the field.
Abstract
Multi-ubiquitin chains at least four subunits long are required for efficient recognition and degradation of ubiquitylated proteins by the proteasome, but other functions of ubiquitin have been discovered that do not involve the proteasome. Some proteins are modified by a single ubiquitin or short ubiquitin chains. Instead of sending proteins to their death through the proteasome, monoubiquitylation regulates processes that range from membrane transport to transcriptional regulation.
This is a preview of subscription content,access via your institution
Access options
Subscription info for Japanese customers
We have a dedicated website for our Japanese customers. Please go tonatureasia.com to subscribe to this journal.
Prices may be subject to local taxes which are calculated during checkout





Similar content being viewed by others
References
Chau, V. et al. A multiubiquitin chain is confined to specific lysine in a targeted short-lived protein.Science243, 1576? 1583 (1989).
Thrower, J. S., Hoffman, L., Rechsteiner, M. & Pickart, C. M. Recognition of the polyubiquitin proteolytic signal.EMBO J. 19, 94?102 (2000).
Hochstrasser, M. Ubiquitin-dependent protein degradation.Annu. Rev. Genet. 30, 405?439 (1996).
Voges, D., Zwickl, P. & Baumeister, W. The 26S proteasome: a molecular machine designed for controlled proteolysis.Annu. Rev. Biochem.68, 1015?1068 (1999).
Galan, J. M. & Haguenauer-Tsapis, R. Ubiquitin Lys63 is involved in ubiquitination and endocytosis of a yeast plasma membrane protein. EMBO J.16, 5847?5854 ( 1997).
Terrell, J., Shih, S., Dunn, R. & Hicke, L. A function for monoubiquitination in the internalization of a G protein-coupled receptor.Mol. Cell1, 193?202 ( 1998).This paper shows that monoubiquitylation on a single lysine residue is necessary and sufficient for rapid endocytosis of an activated signal-transducing receptor in yeast.
Hofmann, R. M. & Pickart, C. M. Noncanonical MMS2-encoded ubiquitin-conjugating enzyme functions in assembly of novel polyubiquitin chains for DNA repair .Cell96, 645?653 (1999).
Deng, L. et al. Activation of the IκB kinase complex by TRAF6 requires a dimeric ubiquitin-conjugating enzyme complex and a unique polyubiquitin chain .Cell103, 351?361 (2000).
Spence, J.et al. Cell-cycle-regulated modification of the ribosome by a variant multiubiquitin chain.Cell102, 67? 76 (2000).
Busch, H. & Goldknopf, I. L. Ubiquitin-protein conjugates .Mol. Cell. Biochem.40, 173? 187 (1981).
van Holde, K. E. Chromatin (Springer, New York, 1988).
Spencer, V. A. & Davie, J. R. Role of covalent modifications of histones in regulating gene expression.Gene 240, 1?12 (1999).
Robzyk, K., Recht, J. & Osley, M. A. Rad6-dependent ubiquitination of histone H2B in yeast .Science287, 501?504 (2000).Although histones H2A and H2B were known to be monoubiquitylated for more than two decades, this paper provided the first evidence that histone ubiquitylation was important for function. Yeast mutants that cannot ubiquitylate histone H2B grow more slowly than wild-type cells and do not sporulate.
Pham, A. D. & Sauer, F. Ubiquitin-activating/conjugating activity of TAF(II)250, a mediator of activation of gene expression inDrosophila.Science289, 2357? 2360 (2000).Drosophila histone H1 is monoubiquitylated by TAF250, an unusual multifunctional protein that seems to carry E1 and E2 activities in the same polypeptide. TAF250 ubiquitylation of H1 seems to be important for the proper regulation of transcriptional activity inDrosophila embryos.
Jentsch, S., McGrath, J. P. & Varshavsky, A. The yeast DNA repair geneRAD6 encodes a ubiquitin-conjugating enzyme.Nature329, 131? 134 (1987).
Prakash, L. The structure and function ofRAD6 andRAD18 DNA repair genes ofSaccharomyces cerevisiae.Genome31, 597?600 (1989).
Roest, H. P. et al. Inactivation of the HR6B ubiquitin-conjugating DNA repair enzyme in mice causes male sterility associated with chromatin modification .Cell86, 799?810 (1996).
Hicke, L. Gettin' down with ubiquitin: turning off cell surface receptors, transporters and channels.Trends Cell Biol.9, 107? 112 (1999).
Rotin, D., Staub, O. & Haguenauer-Tsapis, R. Ubiquitination and endocytosis of plasma membrane proteins: Role of Nedd4/Rsp5p family of ubiquitin-protein ligases.J. Membr. Biol.176, 1?17 ( 2000).
Strous, G., van Kerkhof, P., Govers, R., Ciechanover, A. & Schwartz, A. L. The ubiquitin conjugation system is required for ligand-induced endocytosis and degradation of the growth hormone receptor.EMBO J.15, 3806? 3812 (1996).
Staub, O.et al. Regulation of stability and function of the epithelial Na+ channel (ENaC) by ubiquitination.EMBO J. 16, 6325?6336 (1997).
Bonifacino, J. S. & Weissman, A. M. Ubiquitin and the control of protein fate in the secretory and endocytic pathways. Annu. Rev. Cell Dev. Biol.14, 19? 57 (1998).
Levkowitz, G. et al. c-Cbl/Sli-1 regulates endocytic sorting and ubiquitination of the epidermal growth factor receptor.Genes Dev. 12, 3663?3674 (1998).
Lee, P. S. et al. The Cbl protooncoprotein stimulates CSF-1 receptor multiubiquitination and endocytosis, and attenuates macrophage proliferation.EMBO J.18, 3616?3628 ( 1999).
Levkowitz, G. et al. Ubiquitin ligase activity and tyrosine phosphorylation underlie suppression of growth factor signaling by c-Cbl/Sli-1.Mol. Cell4, 1029?1040 ( 1999).
Jeffers, M., Taylor, G. A., Weidner, K. M., Omura, S. & Vande Woude, G. F. Degradation of the Met tyrosine kinase receptor by the ubiquitin?proteasome pathway.Mol. Cell. Biol.17, 799?808 (1997).
Lucero, P., Penalver, E., Vela, L. & Lagunas, R. Monoubiquitination is sufficient to signal internalization of the maltose transporter in Saccharomyces cerevisiae.J. Bacteriol.182, 241?243 (2000).
Nakatsu, F. et al. A di-leucine signal in the ubiquitin moiety: possible involvement in ubiquitin-mediated endocytosis.J. Biol. Chem.275, 26213?26219 (2000).
Roth, A. F. & Davis, N. G. Ubiquitination of the PEST-like endocytosis signal of the yeast a-factor receptor.J. Biol. Chem.275, 8143?8153 ( 2000).
Springael, J. Y., Galan, J. M., Haguenauer-Tsapis, R. & André, B. NH4+-induced down-regulation of theSaccharomyces cerevisiae Gap1p permease involves its ubiquitination with lysine-63-linked chains .J. Cell Sci.112, 1375? 1383 (1999).
Shih, S. C., Sloper-Mould, K. E. & Hicke, L. Monoubiquitin carries a novel internalization signal that is appended to activated receptors.EMBO J.19, 187?198 (2000).
van Delft, S., Govers, R., Strous, G., Verkleij, A. & Van Bergen en Henegouwen, P. Epidermal growth factor induces ubiquitination of Eps15.J. Biol. Chem.272, 14013? 14016 (1997).
Wilde, A.et al. EGF receptor signaling stimulates SRC kinase phosphorylation of clathrin, influencing clathrin redistribution and EGF uptake. Cell96, 677?687 ( 1999).
Fischer-Vize, J. A., Rubin, G. M. & Lehmann, R. Thefat facets gene is required forDrosophila eye and embryo development.Development116, 985?1000 (1992).
Cadavid, A. L., Ginzel, A. & Fischer, J. A. The function of theDrosophila Fat facets deubiquitinating enzyme in limiting photoreceptor cell number is intimately associated with endocytosis.Development127, 1727?1736 (2000).
Garoff, H., Hewson, R. & Opstelten, D. J. E. Virus maturation by budding.Microbiol. Mol. Biol. Rev.62, 1171?1190 (1998).
Strack, B., Calistri, A., Accola, M. A., Palú, G. & Göttlinger, H. G. A role for ubiquitin ligase recruitment in retrovirus release.Proc. Natl Acad. Sci. USA97, 13063?13068 ( 2000).This paper shows that ubiquitin is important for virus budding and brings ubiquitin protein ligases into the picture. The proline-rich motifs in viral L domains that mediate interaction with ubiquitin protein ligases are required for Gag ubiquitylation and virus budding.
Ott, D. E. et al. Ubiquitin is covalently attached to the p6Gag proteins of human immunodeficiency virus type 1 and simian immunodeficiency virus and to the p12Gag protein of Moloney murine leukaemia virus.J. Virol.72, 2962?2968 ( 1998).
Patnaik, A., Chau, V. & Wills, J. W. Ubiquitin is part of the retrovirus budding machinery .Proc. Natl Acad. Sci. USA97, 13069? 13074 (2000).Depletion of intracellular ubiquitin levels inhibits virus budding at a late stage and this defect can be partially restored by fusing ubiquitin in-frame to Gag. This provides evidence that ubiquitylation of Gag is required for release of virus particles from the host cell.
Schubert, U. et al. Proteasome inhibition interferes with Gag polyprotein processing, release and maturation of human immunodeficiency viruses.Proc. Natl Acad. Sci. USA97, 13057?13062 (2000).
Craven, R. C., Harty, R. N., Paragas, J., Palese, P. & Wills, J. W. Late domain function identified in the vesicular stomatitis virus M protein by use of rhabdovirus-retrovirus chimeras.J. Virol.73, 3359? 3365 (1999).
Jayakar, H. R., Murti, K. G. & Whitt, M. A. Mutations in the PPPY motif of vesicular stomatitis virus matrix protein reduce virus budding by inhibiting a late step in virion release.J. Virol.74, 9818? 9827 (2000).
Harty, R. N., Brown, M. E., Wang, G., Huibregtse, J. & Hayes, F. P. A PPxY motif within the VP40 protein of Ebola virus interacts physically and functionally with a ubiquitin ligase: implications for filovirus budding.Proc. Natl Acad. Sci. USA97, 13871?13876 (2000).
Puffer, B. A., Watkins, S. C. & Montelaro, R. C. Equine infectious anemia virus Gag polyprotein late domain specifically recruits cellular AP-2 adapter protein complexes during virion assembly.J. Virol.72, 10218? 10221 (1998).
Hicke, L. & Riezman, H. Ubiquitination of a yeast plasma membrane receptor signals its ligand-stimulated endocytosis.Cell84, 277?287 ( 1996).
Galan, J. M., Moreau, V., André, B., Volland, C. & Haguenauer-Tsapis, R. Ubiquitination mediated by the Npi1p/Rsp5p ubiquitin-protein ligase is required for endocytosis of the yeast uracil permease.J. Biol. Chem.271, 10946?10952 (1996).
Cook, W., Jeffrey, L., Kasperek, E. & Pickart, C. Structure of tetraubiquitin shows how multiubiquitin chains can be formed .J. Mol. Biol.236, 601? 609 (1994).
Beal, R., Deveraux, Q., Xia, G., Rechsteiner, M. & Pickart, C. Surface hydrophobic residues of multiubiquitin chains essential for proteolytic targeting.Proc. Natl Acad. Sci. USA93, 861?866 ( 1996).
Sloper-Mould, K. E., Jemc, J., Pickart, C. M. & Hicke, L. Distinct functional surface regions on ubiquitin (submitted).
Hochstrasser, M. Evolution and function of ubiquitin-like protein-conjugation systems. Nature Cell Biol.2, E153?E157 (2000).
Schauber, C. et al. Rad23 links DNA repair to the ubiquitin/proteasome pathway .Nature391, 715?718 (1998).
Kleijnen, M. F. et al. The hPLIC proteins may provide a link between the ubiquitination machinery and the proteasome.Mol. Cell6, 409?419 (2000).
Mizushima, N., Noda, T. & Ohsumi, Y. Apg16p is required for the function of the Apg12p?Apg5p conjugate in the yeast autophagy pathway.EMBO J.18, 3888?3896 (1999).
Guarino, L. A., Smith, G. & Dong, W. Ubiquitin is attached to membranes of baculovirus particles by a novel type of phospholipid anchor.Cell80, 301? 309 (1995).
Medintz, I., Jiang, H. & Michels, C. A. The role of ubiquitin conjugation in glucose-induced proteolysis ofSaccharomyces maltose permease.J. Biol. Chem.273, 34454?34462 ( 1998).
Dunn, R. & Hicke, L. Domains of the Rsp5 ubiquitin protein ligase required for receptor-mediated and fluid-phase endocytosis. Mol. Biol. Cell12, 421?435 (2001).
Huibregtse, J. M., Yang, J. G. & Beaudenon, S. L. The large subunit of RNA polymerase II is a substrate of the Rsp5 ubiquitin-protein ligase.Proc. Natl Acad. Sci. USA94, 3656?3661 ( 1997).
Koegl, M.et al. A novel ubiquitination factor, E4, is involved in multiubiquitin chain assembly.Cell96, 635? 644 (1999).
Ortolan, T. G. et al. The DNA repair protein Rad23 is a negative regulator of multi-ubiquitin chain assembly.Nature Cell Biol.2, 601 ?608 (2000).
Finley, D., Bartel, B. & Varshavsky, A. The tails of ubiquitin precursors are ribosomal proteins whose fusion to ubiquitin facilitates ribosome biogenesis.Nature338, 394?401 ( 1989).
Wolffe, A. Chromatin Structure and Function (Academic, San Diego, 1998).
Strahl, B. D. & Allis, C. D. The language of covalent histone modifications.Nature403, 41? 45 (2000).
Ball, E.et al. Arthrin, a myofibrillar protein of insect flight muscle, is an actin?ubiquitin conjugate.Cell51, 221?228 (1987).
Huang, H.et al. The inhibitor of apoptosis, cIAP2, functions as a ubiquitin-protein ligase and promotesin vitro monoubiquitination of caspases 3 and 7 .J. Biol. Chem.275, 26661? 26664 (2000).
Arnason, T. & Ellison, M. J. Stress resistance inSaccharomyces cerevisiae is strongly correlated with assembly of a novel type of multiubiquitin chain.Mol. Cell. Biol.14, 7876? 7883 (1994).
Baboshina, O. V. & Haas, A. L. Novel multiubiquitin chain linkages catalyzed by the conjugating enzymes E2EPF and RAD6 are recognized by 26S proteasome subunit 5.J. Biol. Chem.271, 2823?2831 (1996).
Luger, K., Mader, A. W., Richmond, R. K., Sargent, D. F. & Richmond, T. J. Crystal structure of the nucleosome core particle at 2.8 Å resolution.Nature389, 251?260 (1997).
Joazeiro, C. A. et al. The tyrosine kinase negative regulator c-Cbl as a RING-type, E2-dependent ubiquitin-protein ligase.Science286, 309?312 (1999).
Staub, O.et al. WW domains of Nedd4 bind to the proline-rich PY motifs in the epithelial Na+ channel deleted in Liddle's syndrome. EMBO J.15, 2371?2380 ( 1996).
Overton, M. C. & Blumer, K. J. G-protein-coupled receptors function as oligomersin vivo.Curr. Biol. 10, 341?344 (2000).
Yesilaltay, A. & Jenness, D. D. Homo-oligomeric complexes of the yeast a-factor pheromone receptor are functional units of endocytosis.Mol. Biol. Cell11, 2873? 2884 (2000).
Wilkinson, K. D. & Hochstrasser, M. inUbiquitin and the Biology of the Cell (eds Peters, J. M., Harris, J. R. & Finley, D.) 99?125 (Plenum, New York and London, 1998).
Acknowledgements
I thank R. Lamb, J. Widom, J. Wills and members of my lab for advice and helpful discussions, and R. Lamb and K. Lee for critical comments on the manuscript. J. Wills, H. Göttlinger, U. Schubert and J. Leis generously communicated unpublished results. I apologize to my colleagues whose work or references were not included owing to space restrictions.
Author information
Authors and Affiliations
Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University Evanston, Illinois, 60208, USA
Linda Hicke
- Linda Hicke
You can also search for this author inPubMed Google Scholar
Related links
Related links
DATABASE LINKS
FURTHER INFORMATION
ENCYCLOPEDIA OF LIFE SCIENCES
Glossary
- HISTONE
A family of small, highly conserved basic proteins, found in the chromatin of all eukaryotic cells, that associate with DNA to form a nucleosome.
- ENDOCYTOSIS
Internalization and transport of extracellular material and plasma membrane proteins from the cell surface to intracellular organelles known as endosomes.
- RETROVIRUS
RNA virus that uses reverse transcriptase to convert its RNA into DNA.
- NUCLEOSOME
The basic structural subunit of chromatin, which consists of∼200 base pairs of DNA and an octamer of histones.
- SPORULATION
Sexual reproduction in yeast and fungi.
- UBIQUITIN-CONJUGATING ENZYME (E2)
An enzyme that accepts ubiquitin from a ubiquitin-activating enzyme (E1) and, together with a ubiquitin ligase (E3), transfers it to a substrate protein.
- TAF250
A subunit of TFIID, where TAF stands for TBP-associated factor, and TBP stands for TATA-box-binding protein.
- TFIID
Transcription factor IID. A multisubunit general transcription factor, necessary for the transcription of all genes in eukaryotes.
- LYSOSOME
A membrane-bounded organelle with a low internal pH (4?5) that contains hydrolytic enzymes and that is the site of the degradation of proteins in both the biosynthetic and the endocytic pathways.
- EPS15
Epidermal growth factor receptor pathway substrate clone 15. Mammalian protein required for budding of clathrin-coated vesicles during endocytosis.
- CLATHRIN
The main component of the coat that is associated with clathrin-coated vesicles, which are involved in membrane transport both in the endocytic and biosynthetic pathways.
- DE-UBIQUITYLATING ENZYME
Enzyme that catalyses the cleavage of ubiquitin from multi-ubiquitin chains or protein conjugates.
- GROWTH HORMONE RECEPTOR
A signal transducing receptor of the tyrosine-kinase family.
- GAG
The protein of the nucleocapsid shell around the RNA of a retrovirus.
- POLYPROTEIN
A single polypeptide chain that is cleaved into several separate proteins.
- UBIQUITIN PROTEIN LIGASE (E3)
An enzyme that acts together with a ubiquitin-conjugating enzyme (E2) to couple the small protein ubiquitin to lysine residues on a target protein, marking that protein for destruction by the proteasome.
- SCANNING ALANINE MUTAGENESIS
A method for determining the function of every residue in a protein sequence by mutating each one to alanine.
- CULLIN
A family of proteins present in multisubunit ubiquitin ligases; they recruit RING-finger-containing proteins to the ligase complex.
- SCF UBIQUITIN LIGASE
A multisubunit ubiquitin ligase that contains Skp1, a member of the cullin family (Cul1), and an F-box-containing protein (Skp2), as well as a RING-finger-containing protein (Roc1/Rbx1).
- GATE-16
Protein with a ubiquitin fold, required for intra-Golgi transport and autophagy.
- CHAPERONE
A protein that ensures the proper folding of other proteins.
Rights and permissions
About this article
Cite this article
Hicke, L. Protein regulation by monoubiquitin .Nat Rev Mol Cell Biol2, 195–201 (2001). https://doi.org/10.1038/35056583
Issue Date:
Share this article
Anyone you share the following link with will be able to read this content:
Sorry, a shareable link is not currently available for this article.
Provided by the Springer Nature SharedIt content-sharing initiative