STAM-AMSH interaction facilitates the deubiquitination activity in the C-terminal AMSH

Korea University, Sŏul, Seoul, South Korea
Biochemical and Biophysical Research Communications (Impact Factor: 2.28). 01/2007; 351(3):612-8. DOI: 10.1016/j.bbrc.2006.10.068
Source: PubMed

ABSTRACT Signal transducing adaptor molecule (STAM) complexed with hepatocyte growth factor regulated tyrosine kinase substrate (Hrs) works on sorting of cargo proteins in multivesicular body (MVB) pathway. Associated molecule with SH3 domain of STAM (AMSH), a zinc-containing ubiquitin isopeptidase, is thought to play a role in regulation of ubiquitin-mediated degradation by binding to STAM. We have found that AMSH requires the conformation of Px(V/I)(D/N)RxxKP sequence to bind SH3 domain of STAM with approximately 7 microM affinity, and that the isolated C-terminal domain of AMSH contains the isopeptidase activity. Deubiquitination by AMSH was assisted when ubiquitins were bound to STAM which can bind to AMSH simultaneously. With the specificity toward K63-linked ubiquitins, this facilitated ubiquitin processing activity of AMSH may imply a distinct regulatory mechanism for sorting and degradation through STAM binding.

Download full-text


Available from: Hyun Kyu Song, Dec 26, 2013
  • [Show abstract] [Hide abstract]
    ABSTRACT: Isothermal titration calorimetry (ITC) is a fast and robust method to determine the energetics of association reactions in solution. The changes in enthalpy, entropy and heat capacity that accompany binding provide unique insights into the balance of forces driving association of molecular entities. ITC is used nowadays on a day-to-day basis in hundreds of laboratories. The method aids projects both in basic and practice-oriented research ranging from medicine and biochemistry to physical chemistry and material sciences. Not surprisingly, the range of studies utilizing ITC data is steadily expanding. In this review, we discuss selected results and ideas that have accumulated in the course of the year 2006, the focus being on biologically relevant systems. Theoretical developments, novel applications and studies that provide a deeper level of understanding of the energetic principles of biological function are primarily considered. Following the appearance of a new generation of titration calorimeters, recent papers provide instructive examples of the synergy between energetic and structural approaches in biomedical and biotechnological research.
    Journal of Molecular Recognition 01/2008; 21(1):1-19. DOI:10.1002/jmr.859 · 2.34 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Protein modification by ubiquitin and ubiquitin-like molecules is a critical regulatory process. Like most regulated protein modifications, ubiquitination is reversible. Deubiquitination, the reversal of ubiquitination, is quickly being recognized as an important regulatory strategy. Nearly one hundred human DUBs (deubiquitinating enzymes) in five different gene families oppose the action of several hundred ubiquitin ligases, suggesting that both ubiquitination and its reversal are highly regulated and specific processes. It has long been recognized that ubiquitin ligases are modular enzyme systems that often depend on scaffolds and adaptors to deliver substrates to the catalytically active macromolecular complex. Although many DUBs bind ubiquitin with reasonable affinities (in the nM to microM range), a larger number have little affinity but exhibit robust catalytic capability. Thus it is apparent that these DUBs must acquire their substrates by binding the target protein in a conjugate or by associating with other macromolecular complexes. We would then expect that a study of protein partners of DUBs would reveal a variety of substrates, scaffolds, adaptors and ubiquitin receptors. In the present review we suggest that, like ligases, much of the regulation and specificity of deubiquitination arises from the association of DUBs with these protein partners.
    Biochemical Journal 10/2008; 414(2):161-75. DOI:10.1042/BJ20080798 · 4.78 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Deubiquitinating enzymes (DUBs) remove ubiquitin from conjugated substrates to regulate various cellular processes. The Zn2+-dependent DUBs AMSH and AMSH-LP regulate receptor trafficking by specifically cleaving Lys63-linked polyubiquitin chains from internalized receptors. Here we report the crystal structures of the human AMSH-LP DUB domain alone and in complex with a Lys63-linked di-ubiquitin at 1.2Å and 1.6Å resolutions, respectively. The AMSH-LP DUB domain consists of a Zn2+-coordinating catalytic core and two characteristic insertions, Ins-1 and Ins-2. The distal ubiquitin interacts with Ins-1 and the core, whereas the proximal ubiquitin interacts with Ins-2 and the core. The core and Ins-1 form a catalytic groove that accommodates the Lys63 side chain of the proximal ubiquitin and the isopeptide-linked carboxy-terminal tail of the distal ubiquitin. This is the first reported structure of a DUB in complex with an isopeptide-linked ubiquitin chain, which reveals the mechanism for Lys63-linkage-specific deubiquitination by AMSH family members.
    Nature 12/2008; 456(7219):274. DOI:10.1038/nature07515 · 42.35 Impact Factor
Show more