Dange T, et al. (2011) Blm10 protein promotes proteasomal substrate turnover by an active gating mechanism. J Biol Chem 286(50):42830-9
Abstract: For optimal proteolytic function, the central core of the proteasome (core particle (CP) or 20S) has to associate with activators. We investigated the impact of the yeast activator Blm10 on proteasomal peptide and protein degradation. We found enhanced degradation of peptide substrates in the presence of Blm10 and demonstrated that Blm10 has the capacity to accelerate proteasomal turnover of the unstructured protein tau-441 in vitro. Mechanistically, proteasome activation requires the opening of a closed gate, which allows passage of unfolded proteins into the catalytic chamber. Our data indicate that gate opening by Blm10 is achieved via engagement of its C-terminal segment with the CP. Crucial for this activity is a conserved C-terminal YYX motif, with the penultimate tyrosine playing a preeminent role. Thus, Blm10 utilizes a gate opening strategy analogous to the proteasomal ATPases HbYX-dependent mechanism. Because gating incompetent Blm10 C-terminal point mutants confers a loss of function phenotype, we propose that the cellular function of Blm10 is based on CP association and activation to promote the degradation of proteasome substrates.
|Status: Published||Type: Journal Article | Research Support, N.I.H., Extramural | Research Support, Non-U.S. Gov't||PubMed ID: 22025621|
Topics addressed in this paper
Number of different genes curated to this paper: 8
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|Fungal Related Genes/Proteins|
|Non-Fungal Related Genes/Proteins|
|Protein Physical Properties|
|Protein Sequence Features|
|Protein/Nucleic Acid Structure|