Protein Trafficking

Protein trafficking refers to the highly regulated series of processes by which proteins are synthesised, folded, modified and transported to their final destinations within or outside the cell. Secretory and membrane proteins usually enter the endoplasmic reticulum (ER), where they acquire native conformation and undergo quality control. They are then packaged into vesicles that bud from the ER, travel via the Golgi apparatus for further modification and are sorted into post-Golgi carriers for delivery to the plasma membrane, endosomes or lysosomes. A parallel endocytic pathway internalises surface receptors and nutrients, passing them through early and late endosomes before recycling or degradation. Key factors include coat proteins that drive vesicle formation, adaptors and cargo receptors that ensure selective sorting, motor proteins that steer vesicles along cytoskeletal tracks, tethering factors that capture vesicles at target membranes and SNARE proteins that catalyse membrane fusion. The balance of anterograde and retrograde transport sustains organelle identity and protein homeostasis. Disruption of these pathways underpins a spectrum of diseases, from congenital glycosylation disorders and neurodegeneration to cancer and immune dysfunction. Advances in live-cell imaging, high-throughput screening and structural biology have begun to illuminate the dynamic choreography of the trafficking machinery and its adaptation to cellular demands.

Research from Nature Portfolio

Recent proteomic and transcriptomic studies in human neuronal models have revealed how dysfunction of the retromer complex—a core endosomal sorting assembly—leads to widespread remodelling of the lysosomal proteome, defects in autophagic lysosome reformation and compensatory lysosomal exocytosis. These findings underscore the critical neuroprotective role of retromer-mediated retrieval of integral membrane proteins and highlight its importance in maintaining endo-lysosomal health. In parallel, a comparative proteomics approach has mapped the specialised trafficking pathway of α5 integrin in endothelial cells, demonstrating that neuropilin-1 and neuropilin-2 co-associate with α5 integrin in endosomal compartments and direct its transit through a Rab11-positive recycling route. This mechanism promotes polarised fibronectin assembly and endothelial sprouting, revealing how co-receptors and adaptor proteins coordinate receptor recycling to drive morphogenetic processes.

Protein Trafficking publication trend

The graph below shows the total number of articles in protein trafficking across all publications each year (not limited to Nature Index journals).

Technical terms

Vesicle: A small, membrane-bound carrier that transports proteins between cellular compartments.

Coat protein complex II (COPII): A cytosolic coat that assembles on the ER membrane to package cargo into vesicles destined for the Golgi.

Cargo receptor: A transmembrane protein that binds soluble or membrane cargo in the lumen or membrane of one compartment and links it to coat proteins for selective packaging.

SNARE proteins: A family of membrane-anchored proteins whose specific pairing drives the fusion of transport vesicles with target membranes.

Retromer complex: An endosomal sorting assembly that retrieves specific transmembrane proteins from endosomes back to the Golgi or plasma membrane.

References

1. Multi-omic approach characterises the neuroprotective role of retromer in regulating lysosomal health. Nature Communications (2023).
2. A proteomics approach to isolating neuropilin-dependent α5 integrin trafficking pathways: neuropilin 1 and 2 co-traffic α5 integrin through endosomal p120RasGAP to promote polarised fibronectin fibrillogenesis in endothelial cells. Communications Biology (2024).
3. Mechanisms of Protein Trafficking and Quality Control in the Kidney and Beyond. Annual Review of Physiology (2023).
4. Cargo selection in endoplasmic reticulum–to–Golgi transport and relevant diseases. Journal of Clinical Investigation (2023).