By Ana Espino | Published on February 10, 2026 | 3 min readG protein-coupled receptors (GPCRs) are central to cellular signaling. They regulate key physiological functions—cardiovascular, neurological, immune—and account for nearly one-third of all current drug targets. Traditionally, GPCRs were thought to function exclusively at the plasma membrane, where they initiate rapid and transient intrace
By Ana Espino | Published on February 10, 2026 | 3 min read
G protein-coupled receptors (GPCRs)
are central to cellular signaling. They regulate key physiological
functions—cardiovascular, neurological, immune—and account for nearly one-third
of all current drug targets. Traditionally, GPCRs were thought to function exclusively
at the plasma membrane, where they initiate rapid and transient
intracellular signaling via G proteins and β-arrestins.
However, this classical view is now
showing its limits. Growing evidence reveals that GPCRs can also signal from
intracellular compartments such as the endosomes, the Golgi
apparatus, and even the nucleus, producing distinct and often
prolonged effects. Traditional pharmacological tools lack the spatial
resolution to differentiate these signals based on their subcellular origin,
limiting our ability to design specific, localized, and more effective drugs.
In response, an emerging therapeutic
approach involves using chemical biology tools to visualize,
modulate, and decode GPCR signaling within intracellular compartments. This
strategy offers a unique opportunity to create a dynamic and
compartmentalized map of signaling pathways.
This study was therefore initiated
to review recent chemical biology-based approaches that help unravel intracellular
GPCR signaling, and to assess their potential for transforming targeted
pharmacology.
Can we trace intracellular signals?
This review highlights the use of compartment-targeted
chemical probes that can activate or inhibit GPCRs in specific locations
such as endosomes or the Golgi apparatus. It also presents optogenetic
and chemogenetic tools that enable spatiotemporal control of GPCR
activation. Additionally, intracellular FRET/BRET biosensors are
discussed, designed to detect G protein or β-arrestin activation in defined subcellular
regions, along with molecular targeting platforms that use localization
signals to redirect receptors or their effectors to specific compartments. The evidence confirms that GPCRs are
not limited to plasma membrane signaling. Distinct signals also arise
from endosomes, the Golgi, and occasionally non-conventional
organelles, influencing the duration, intensity, and quality
of cellular responses. This intracellular signaling landscape could explain the
differential effects observed with certain ligands, and paves the way
for the development of more precise, spatially targeted, and functionally
selective therapeutics.
Toward 3D pharmacology?
GPCRs are critical pharmacological
targets, yet their intracellular signaling remains largely unexplored.
The main current challenge lies in the inability of conventional tools to distinguish
signals based on subcellular origin, which limits the precision of targeted
therapies. This review aimed to shed light on recently developed chemical
biology tools that allow for the analysis and modulation of GPCR signaling
within specific cellular compartments. It demonstrates that the subcellular
localization of a receptor profoundly influences the nature, duration, and
strength of its signaling, opening new avenues for more refined and
personalized pharmacological strategies.
However, limitations remain and
further research is warranted. These future directions will include refining subcellular targeting
tools, integrating dynamic data into more complex cellular models,
and conducting in vivo functional studies to evaluate the physiopathological
consequences of compartmentalized signaling. It will also be essential to
better link these localized signals to whole-cell pharmacological responses,
to ultimately develop drugs that act precisely where the signal truly
originates.
About the author – Ana Espino PhD in Immunology, specialized in Virology As a scientific writer, Ana is passionate about bridging the gap between research and real-world impact. With expertise in immunology, virology, oncology, and clinical studies, she makes complex science clear and accessible. Her mission: to accelerate knowledge sharing and empower evidence-based decisions through impactful communication.
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Scientific reference
Bock A, et al. Chemical biology approaches to resolve the subcellular GPCR signaling landscape. Nat Chem Biol. 2025 Aug;21(8):1148-1159
