Featured Resources
-
STORM Therapeutics: From Lead to Pre-Candidate Nomination in 18 Months
STORM Therapeutics: From Lead to Pre-Candidate Nomination in 18 Months
Case study
The challenges in pursuing a membrane protein as a drug target
Membrane proteins, such as ion channels, G protein–coupled receptors (GPCRs), and transporters, continue to represent some of the most important therapeutic targets, yet they are also among the most technically challenging to study , especially within a drug discovery context. As a result, the success of a project is not defined solely by identifying the right biological target to interrogate, but also by choosing a partner with the expertise and integrated capabilities needed to fully unlock its potential.
At the heart of this challenge lies the inherently multidisciplinary nature of membrane protein research. Effective drug discovery in this space requires not only an understanding of biological function in a cellular context but also a detailed grasp of molecular structure and mechanism.
Historically, these two dimensions—functional biology and protein science—have often been pursued separately. However, this separation can limit insight and slow progress. Increasingly, the most successful approaches are those that combine both perspectives within a single, cohesive workflow.
The need for cell-based assay systems…..
Functional insight begins at the cellular level, where membrane proteins carry out their roles in a physiologically relevant environment. Ion channels, for example, require precise measurement of electrical activity or ion flux, while GPCRs depend on a multitude of pathway-specific signalling assays to accurately capture receptor behaviour. Transporters, meanwhile, require carefully engineered systems with the sensitivity to monitor substrate movement across membranes. Developing robust cell-based assays therefore depends on high-quality cell line engineering, from construct design to rigorous clone selection and thoughtful assay design. The added benefit of course is that the membrane protein will be in its natural state with the correct post translational modifications such as glycosylation that can influence the functional activity. When executed effectively, these cellular assay systems provide a highly relevant and predictive platform for screening and identifying promising drug candidates.
An Overview of the cell-based assays available at Sygnature Discovery
- >150 Ion Channels with >200 validated cell lines & assays
- >250 GPCRs with >100 validated cell lines & assays
- >30 Transporters with >30 validated cell lines & assays
…….Backed up by purified protein and ideally a structural system
It’s clear however that functional cell data alone is not sufficient. Without an accompanying understanding of structure, researchers risk identifying compounds that demonstrate activity but lack a clear mechanism of action. This is where protein science plays a critical role. By generating stabilised protein constructs, scientists can enable detailed biophysical and structural characterisation. Purified proteins support binding studies, while high-resolution structural data informs medicinal chemistry decisions and guides optimisation efforts.
Together, these approaches provide a molecular-level view of how compounds interact with their targets—information that is essential for rational drug design.
To this end, within the Protein Science department at Sygnature we have a dedicated membrane protein team, supported by full cryo-EM, X-ray crystallography and NMR capabilities.
DMPK and in vivo support
In the latter stages of a project, it is also clearly beneficial to have a CRO that can provide DMPK data and relevant in vivo disease model support to fully characterize the lead molecules.
Other services and capabilities
Beyond this, access to a full suite of capabilities such as computer aided drug design, biophysical assays, medicinal chemistry and form and formulation where scientists can share data, discuss the implications and respond accordingly will have a significant positive impact on timelines for a membrane protein drug discovery project.
5-HT2a Receptor: An example of where Sygnature is able to provide an integrated support platform for a membrane protein drug target
Below we present a selection of capabilities where we provide support for 5-HT2a receptor drug discovery. With our range of expertise we would look to apply this type of approach to any membrane protein target.
Assay support
We have established a comprehensive set of assays in order to provide a full screening cascade for the 5-HT2a receptor.
- Receptor High throughput screening assays
- Receptor Binding Assays
- Assays to explore compound influence on relevant Signalling Pathways
- Receptor internalization assays
- Comparison of compound affinities against 5-HT2a receptor subtypes in rodent brain samples [read more here]
For GPCR targets often further GPCR assay optimization using chimeric G proteins will enable improved signalling control and enhanced assay performance. [See an example case study here]
5-HT2a Receptor : Gene to cryo-EM structure produced in house
We have generated a cryo-EM structure of the 5-HT2AR [see our case study and also poster] which provided insights into the receptor’s conformation and the binding pose of serotonin. Interestingly, this differs from previous X-ray crystallography structures.
With our dedicated and hugely experienced membrane protein and structural biology teams we are well positioned to tackle any membrane protein target that is of interest to a client that requires either purified protein and/or a structural system.
In vivo studies to further support 5-HT2a drug discovery programs
Furthermore, we have in vivo murine models that can be readily applied to membrane protein targets depending on the disease being tackled. An example of a study with 5-HT2a receptor examined the effects of psilocybin, a psychedelic compound, on head twitches, locomotor activity, 5-HT2A receptor occupancy, and levels of psilocin in mice
The power of choosing the right CRO partner
The true advantage for complex targets such as ion channels, GPCRs and transporters, emerges when these two dimensions integrate within a single organisation. Combining functional biology with biophysical characterisation and structural expertise can deliver a much more complete and connected understanding of membrane protein targets. Functional activity can be cross validated with molecular interaction data, ensuring that observed biological effects are supported by mechanistic insight. Screening campaigns can feed directly into structure-informed design, accelerating iteration and refining compound selection.
The risks of working with multiple partners
In contrast, many organisations still rely on fragmented workflows, outsourcing different aspects of the discovery process to multiple vendors. While this approach may appear flexible, it introduces significant inefficiencies and risks—especially for membrane proteins. Misalignment between cell-based assays and protein constructs can lead to inconsistent or misleading data. Knowledge transfer between vendors is often imperfect, resulting in lost context and duplicated effort. Handoffs create delays, while discrepancies between functional and structural findings can be difficult to reconcile. Ultimately, this fragmentation slows progress and increases uncertainty at precisely the point where clarity is most critical.
The benefits of working with a partner that provides everything
Consistency:
- Comparable data and shared learning
- Consistent construct design across all platforms
- Including any stabilisation mutations, post translational modifications etc.
Improved timelines:
- Smoother communication
- Defined responsibilities and accountabilities
- Simpler decision making
In Summary
As membrane proteins continue to define the frontier of drug discovery, their complexity will remain a constant. The key to overcoming this challenge lies not in simplifying the targets, but in evolving the approach. By partnering with organisations that combine deep target expertise with fully integrated capabilities, companies can transform complexity from a barrier into a source of competitive advantage—unlocking new opportunities for innovation and therapeutic impact.
