Cotransin

Protein target name:

SEC61 complex

Mechanism of action:

Inhibitor

Recommended Concentration for use in cells:

2 uM

Probe Information

Target and Probe Information

Target Details

Target class:

Integral membrane protein

Subclass:

General secrectory pathway

UNIPROT ID:

P61619

Target alias:

SEC61

Probe Details

Chemical Probes Portal ID:

CPP1634

Probe alias:

PubChem CID:

25068231

SMILES string:

C[C@H]1C(=O)O[C@@H](C(=O)N[C@H](C(=O)N([C@H](C(=O)N[C@H](C(=O)N([C@H](C(=O)N[C@H](C(=O)N1C)CC(C)C)CC2=CC=CC=C2)C)CC(C)C)CC(C)C)C)CC(C)C)C

InChi Key:

LTYNXERAWVCPAH-OHRKNAERSA-N

Control compound:

Nor-cotransin

Validation in Cells and Model Organisms

In vitro validation

On target activity

Potency assay:

In synthetic proteoliposomes containing only SEC61 and SR, 10 uM cotransin inhibited VCAM1 translocation but not pre-prolactin. In in vitro transcription/translation assays in reticulocyte lysate with rough endoplasmic reticulum (ER) and microsomes (TNT assays), 10 uM cotransin VCAM1 glycosylation but not translation, and had comparable activity on fusion proteins containing the N-terminal signal sequence from VCAM1. 25 uM cotransin also disrupted cross-linking between ER proteins and Sec61alpha.

Off target activity

Potency assay (off target):

In in vitro TNT assays, cotransin had no affect on pre-prolactin or model type I, type II, and multi-membrane spanning proteins.

In cell validation

On target activity in cells

Potency assay (cells):

In COS-7 cells, 2 uM cotransin inhibited a small subset of secretory and membrane proteins (i.e., VCAM1 and P-selectin). These phenotype was mimicked by depletion of the Sec61 complex.

Primary Reference

Reference (doi):

10.1038/nature03821

Reference (PMID):

16015336

SAB Rating

Rating for use in Cells

3 review(s)

Rating for use in Model Organisms

no rating

SAB Members

SAB Comments

Cotransin is a relatively new probe for Sec61-dependent protein translocation. This probe is the best we have so far, but there is scant information regarding precise mode of on-target action and potential sites of off-target activity. Use of this probe seems limited to lysate-based experiments.

Jul 18 2017 - 11:42am

Because Cotransin is signal sequence specific, it only blocks a certain subset of proteins which are translocated by SEC61. Cotransin analogues have been made which target different proteins which are translocated by SEC61. The Cotransin family of molecules are the best available tools to study SEC61 (Apratoxin, listed in references also targets SEC61 but is cytotoxic), but a better understanding of their selectivity for signal sequences or a comprehensive screen of which proteins are affected by each Cotransin analogue would be necessary to make the use of Cotransin as probes for SEC61 more general. Cotransin has been used at 5µM to block Cotransin sensitive proteins and at 30µM to block the majority of secreted proteins. Membrane integral proteins are not affected by Cotransin at these concentrations.

Mar 12 2020 - 12:02pm

There has been 2015 mechanistic study “Defining a Conformational Consensus Motif in Cotransin-Sensitive Signal Sequences: PMC4373898 but the specificity does not have extensive SAR in particular for an obvious negative control. While more recent studies are optimistic on the possibility of specificity (e.g. “The signal peptide as a new target for drug design” PMID: 32209293) caution is warranted and reported concentrations are high enough to be in a vast stoichiometric excess to the target proteins in the in vitro systems. With more a physical mechanism rather than a specific protein binding pocket interaction this is not a classical probe.

Nov 23 2020 - 11:15am

Cotransin

Probe Information

Target Details

SEC61

Probe Details

In vitro validation

In cell validation

Primary Reference

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Cotransin

Probe Information

Target Details

SEC61

Probe Details

In vitro validation

In cell validation

Primary Reference

Supporting Organizations

Interested in supporting the portal?