ML323

Allosteric inhibitor of USP1, WDR48

Structure

SERP Rating

In Cells

(3 ratings)

In Model Organisms

(0 ratings)

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Information

USP1
WDR48

Allosteric inhibitor

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Probe Availability:

In Vitro Validations

Uniprot ID: O94782

Target Class: Other post-translational modification

Target SubClass: Deubiquitinase

Potency: IC 50

Potency Value: 76 nM

Potency Assay: USP1/UAF1 activity was monitored in a fluorometric ubiquitin−rhodamine110 assay. ML323 also showed IC50s of 174 nM and 820 nM in orthogonal gel-based assays using K63-linked diubiquitin (di-Ub) and monoubiquitinated PCNA (Ub-PCNA) as substrates, respectively.

PDB ID for probe-target interaction (3D structure): --

Structure-activity relationship: Yes, see J. Med. Chem publication for details.

Target aliases:

Ubiquitin carboxyl-terminal hydrolase 1, USP1, UBP ...

DOI Reference: 10.1038/nchembio.1455

In Cell Validations

In Vivo Data

No in Vivo Validations

Off-Target Selectivity Assesments

Potency assay (off target): ML323 showed no notable activity against the USPs (USP2, USP5, USP7, USP8, USP10, USP11, USP14 and USP21). ML323 displayed no notable against DUBs in the ubiquitin C-terminal hydrolase (UCH), ovarian tumor protease (OTU) and Machado-Joseph domain (MJD) families and did not inhibit the deSUMOylase SENP1 or the deneddylase, NEDP1.

Probe Selectivity in Vitro:

ML323 off-target activity was assessed by determining the inhibitory effect of ML323 against 70 unrelated proteases and 451 kinases in in vitro assays; no notable activity was detected.

Potency assay, off target (cells): ML323 did not inhibit the labeling of the DUBs, USP8, USP7, CYLD, USP5, USP14, UCH-L3 and UCH-L1, tested by HA-Ub-VME.

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SERP ratings and comments

SERP Ratings

In Cell Rating

SERP Comments:

ML323 is a selective USP1/UAF1 inhibitor that has been shown to have good Caco-2 permeability and to be efficacious in cellular assays at ≥5 µM. A compound in the same series (compound 77 in J. Med. Chem., 2014, 8099-8110) can be used as an inactive control. ML323 was found to have rapid clearance and has not been proposed for use in vivo.

(last updated: 15 Jan 2017 )

SERP Ratings

In Cell Rating

SERP Comments:

ML323 is an allosteric, selective inhibitor of the USP1/UAF1 complex (also called USP1/WDR48). Note that ML323 is much less effective in inhibiting USP1 alone in biochemical assays. The full implications or relevance of this differential activity in cells has not been explored.

(last updated: 16 Jan 2017 )

SERP Ratings

In Cell Rating

SERP Comments:

ML-323 is a unique, cell-permeable and highly selective inhibitor of the USP1/UAF1 complex. A notable discordance between biochemical and cellular potency for ML-323 is observed, and should be further examined. Furthermore, a more direct, biophysical assessment of intracellular target engagement would be valuable to explore the mechanism of the observed IC50 offset.

(last updated: 22 Jan 2017 )