Discovery and Development of Cyclic Peptide Proteasome Stimulators.

The proteasome degrades proteins, which is essential for cellular homeostasis. Ubiquitin independent proteolysis degrades highly disordered and misfolded proteins. A decline of proteasomal activity has been associated with multiple neurodegenerative diseases due to the accumulation of misfolded proteins.

Identification of a covalent binder to the oncoprotein gankyrin using a NIR-Based OBOC screening method.

Despite huge advancements in the process of synthesizing small molecules as part of one-bead-one-compound (OBOC) libraries, progress lags in the ability to screen these libraries against proteins of interest. Recently, we developed a method to screen OBOC libraries in which a target protein is labeled with a near-infrared (NIR) range fluorophore. The labeled protein incubates with beads of a library in a 96-well plate, then the plate is imaged for fluorescence.

Solid-Phase Synthesis and Application of a Clickable Version of Epoxomicin for Proteasome Activity Analysis.

Degradation of proteins by the proteasome is an essential cellular process and one that many wish to study in a variety of disease types. There are commercially available probes that can monitor proteasome activity in cells, but they typically contain common fluorophores that limit their simultaneous use with other activity-based probes. In order to exchange the fluorophore or incorporate an enrichment tag, the proteasome probe likely has to be synthesized which can be cumbersome.

A Yeast Chronological Lifespan Assay to Assess Activity of Proteasome Stimulators.

Aging is characterized by changes in several cellular processes, including dysregulation of proteostasis. Current research has shown long-lived rodents display elevated proteasome activity throughout life and proteasome dysfunction is linked to shorter lifespans in a transgenic mouse model. The ubiquitin proteasome system (UPS) is one of the main pathways leading to cellular protein clearance and quality maintenance.

Approaches to Evaluate the Impact of a Small-Molecule Binder to a Noncatalytic Site of the Proteasome.

Proteasome activity is crucial for cell survival and proliferation. In recent years, small molecules have been discovered that can affect the catalytic activity of the proteasome. Rather than targeting the active sites of the proteasome, it might be possible to affect ubiquitin-dependent degradation of proteins by limiting the association of the 19S regulatory particle (19S RP) with the 20S core particle (20S CP) of the proteasome.

Methods for the discovery of small molecules to monitor and perturb the activity of the human proteasome.

Regulating protein production and degradation is critical to maintaining cellular homeostasis. The proteasome is a key player in keeping proteins at the proper levels. However, proteasome activity can be altered in certain disease states, such as blood cancers and neurodegenerative diseases.

The Immunoproteasome: An Emerging Target in Cancer and Autoimmune and Neurological Disorders.

The immunoproteasome (iCP) is an isoform of the 20S proteasome that is expressed when cells are stressed or receive an inflammatory signal. The primary role of the iCP is to hydrolyze proteins into peptides that are compatible with being loaded into a MHC-I complex. When the activity of the iCP is dysregulated or highly expressed, it can lead to unwanted cell death.

Development of a Method To Prioritize Protein-Ligand Pairs on Beads Using Protein Conjugated to a Near-IR Dye.

The development of techniques to screen one-bead-one-compound (OBOC) libraries remains a critical step in identifying small molecules that bind target proteins. While great strides have been made, there remains a need to continue to develop OBOC screening techniques that not only reliably identify hit molecules but also can distinguish poor from excellent binders in a single screen. Similarly, relatively strong binding between a small molecule and protein target is required to be considered a hit from the initial pool of screened molecules.