GO:0062137 cargo receptor complex: Components, Assembly and Research Methods, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0062137 cargo receptor complex is a cellular component defined as any protein complex that is part of a membrane and functions as a cargo receptor [QuickGO].
• Cargo receptor complexes selectively bind cargo proteins at membranes and mediate their transport, sorting, or degradation [1, 3, 5].
• The WDR11 complex is a recently identified cargo receptor complex for acidic-cluster-containing cargo proteins.
• NCOA4 is a cargo receptor that mediates ferritinophagy, the selective autophagic degradation of ferritin.
• NDP52 (also known as CALCOCO2) functions as a cargo receptor complex component that recruits the ULK complex to cytosol-invading bacteria, initiating selective autophagy.
• Dysregulation of cargo receptor complexes is implicated in diverse pathologies, including cancer, neurodegeneration, and infections [3, 6, 8].
Description
The Gene Ontology (GO) term GO:0062137, cargo receptor complex, describes a cellular component: any protein complex that is part of a membrane and functions as a cargo receptor [QuickGO]. Cargo receptor complexes are essential for the selective recognition and transport of specific cargo proteins within the endomembrane system, thereby controlling protein sorting, trafficking, and degradation [1, 5, 7]. These complexes operate at various membranes, including the plasma membrane, endosomes, and autophagosomes, and they are critical for maintaining cellular homeostasis [3, 5, 8]. Research into cargo receptor complexes has accelerated in recent years, revealing their roles in fundamental processes such as endocytosis, endosomal sorting, and selective autophagy [1, 3, 8]. For example, the WDR11 complex was identified as a receptor for acidic-cluster-containing cargo proteins, highlighting the diversity of cargo recognition mechanisms. Similarly, NCOA4 mediates ferritinophagy by binding ferritin and delivering it to autophagosomes for degradation. These findings underscore the importance of cargo receptor complexes in health and disease, making them attractive targets for therapeutic intervention. This article provides a comprehensive overview of GO:0062137, covering its definition, structure, molecular mechanisms, key genes, research methods, and relevance to human disease. It is intended for researchers seeking to understand or manipulate cargo receptor complexes using CRISPR-based approaches.
cargo receptor complex At A Glance
| GO ID | GO:0062137 |
|---|---|
| GO term | cargo receptor complex |
| Ontology | cellular_component |
| Synonym | None |
| Major function | Functions as a cargo receptor; binds cargo proteins and mediates their transport, sorting, or degradation [1, 3, 8] |
| Membrane association | Part of a membrane; can be at the plasma membrane, endosomes, autophagosomes, or other organelles [1, 5, 8] |
| Cargo specificity | Recognizes specific cargo proteins, often via sorting signals such as acidic clusters |
| Biological context | Involved in endocytosis, endosomal sorting, selective autophagy, and ferritinophagy [3, 5, 8] |
| Example complex | WDR11 complex (receptor for acidic-cluster-containing cargo) |
What Is GO:0062137?
According to the Gene Ontology, GO:0062137 cargo receptor complex is defined as any protein complex that is part of a membrane and which functions as a cargo receptor [QuickGO]. In other words, it is a membrane-associated assembly of proteins that specifically binds cargo molecules (such as proteins or lipids) and facilitates their transport, sorting, or degradation. This definition emphasizes two key aspects: the complex must be membrane-associated, and it must act as a receptor for cargo. The term does not specify the type of cargo, the membrane system involved, or the downstream fate of the cargo, allowing for a wide range of biological contexts [1, 3, 8].
Why Is cargo receptor complex Important in Cell Biology?
Cargo receptor complexes are central to cellular logistics, ensuring that proteins and other molecules reach the correct destination or are degraded when necessary [1, 5, 7]. Their dysfunction can lead to a wide range of diseases, including cancer, neurodegeneration, and infections [3, 6, 8]. Understanding these complexes is therefore crucial for basic cell biology and for developing targeted therapies.
• Cargo receptor complexes mediate selective protein trafficking, which is essential for cellular homeostasis [1, 5].
• They are key players in selective autophagy, including ferritinophagy and xenophagy [3, 8].
• Mutations or dysregulation of cargo receptor complexes are linked to cancer, neurodegeneration, and infectious diseases [3, 6, 8].
• They provide potential therapeutic targets for brain drug delivery via receptor-mediated transcytosis.
• Cargo receptor complexes are involved in endocytic recycling, influencing cell surface receptor levels.
• They help maintain organelle function by delivering specific cargo to endosomes, lysosomes, and autophagosomes [5, 8].
• Studying cargo receptor complexes can reveal fundamental mechanisms of membrane traffic and protein sorting [1, 5].
• CRISPR-based models of cargo receptor genes enable causal testing of their roles in disease [1, 3, 8].
What Happens During cargo receptor complex?
Cargo Recognition and Binding
In simple terms: The cargo receptor complex grabs onto specific cargo proteins.
Cargo receptor complexes recognize and bind specific cargo proteins through signal sequences or motifs. For example, the WDR11 complex binds acidic-cluster-containing cargo proteins. This recognition is highly selective, ensuring that only appropriate cargo is transported. The binding often occurs at the membrane where the complex resides, such as the trans-Golgi network or endosomes [1, 5].
Complex Assembly and Membrane Association
In simple terms: The receptor complex assembles and attaches to a membrane.
Cargo receptor complexes are composed of multiple protein subunits that assemble into a functional unit. They are integral or peripheral membrane proteins, allowing them to associate with specific organelle membranes [1, 3]. For instance, the WDR11 complex is a multi-protein assembly that includes WDR11 and other subunits, and it localizes to membranes to facilitate cargo recognition. Similarly, NCOA4 is a cargo receptor that binds ferritin and associates with autophagosomal membranes.
Cargo Transport and Sorting
In simple terms: The complex moves the cargo to its destination.
Once bound, the cargo receptor complex mediates the transport of cargo to the appropriate destination, such as endosomes, lysosomes, or the plasma membrane. This can involve vesicular transport, endosomal sorting, or direct delivery to autophagosomes [1, 5, 7]. For example, the WDR11 complex is involved in the transport of acidic-cluster-containing cargo proteins from the Golgi to endosomes. In endocytic recycling, cargo receptor complexes help return receptors to the cell surface.
Cargo Release and Downstream Fate
In simple terms: The cargo is released and either recycled or degraded.
After transport, the cargo is released from the receptor complex, often triggered by changes in pH or other environmental cues. The cargo may then be recycled back to its original location, delivered to a different organelle, or targeted for degradation [5, 7]. In selective autophagy, cargo receptor complexes like NCOA4 deliver cargo (e.g., ferritin) to autophagosomes for degradation. NDP52 recruits the ULK complex to initiate autophagy of cytosol-invading bacteria.
Regulation of Cargo Receptor Complex Activity
In simple terms: The activity of the complex is controlled by various signals.
Cargo receptor complex function is regulated at multiple levels, including protein expression, post-translational modifications, and interactions with other proteins. For instance, phosphorylation of cargo receptors can modulate their binding to cargo or their localization [1, 8]. The availability of cargo and the presence of specific lipids or cofactors also influence complex activity [5, 7]. Dysregulation of these regulatory mechanisms can contribute to disease.
Key Genes Involved in GO:0062137 cargo receptor complex
The following genes encode proteins that are components of or directly associated with cargo receptor complexes, based on published literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| WDR11 | Component of the WDR11 complex, a cargo receptor for acidic-cluster-containing proteins | Studied for its role in Golgi-to-endosome transport and potential links to disease |
| NCOA4 | Cargo receptor for ferritin, mediating ferritinophagy | Key regulator of iron homeostasis; implicated in cancer and neurodegeneration |
| CALCOCO2 (NDP52) | Cargo receptor that recruits ULK complex to bacteria for autophagy | Important for xenophagy and host defense; studied in infection and autoimmunity |
| SQSTM1 (p62) | Cargo receptor for ubiquitinated proteins in selective autophagy | Involved in protein aggregation diseases and cancer |
| OPTN | Cargo receptor in selective autophagy and NF-kB signaling | Mutations linked to glaucoma and ALS |
| TAX1BP1 | Cargo receptor in autophagy and NF-kB regulation | Studied in inflammation and cancer |
| NBR1 | Cargo receptor for ubiquitinated proteins in autophagy | Implicated in proteinopathies |
| TOLLIP | Cargo receptor in autophagy and endosomal sorting | Linked to immunity and neurodegeneration |
| CBL | E3 ubiquitin ligase that can act as a cargo receptor for ubiquitinated receptors | Studied in endocytic sorting and cancer |
| EGFR | Cargo protein that is sorted by cargo receptor complexes | Model cargo for studying receptor trafficking |
| TFRC | Transferrin receptor, a cargo protein in recycling | Classic marker for endocytic recycling |
| LDLR | LDL receptor, cargo for endocytosis | Studied in cholesterol metabolism |
| VPS35 | Component of retromer, a cargo receptor complex for endosomal sorting | Linked to Parkinson's disease |
| SNX1 | Sorting nexin, part of retromer-associated cargo recognition | Studied in endosomal trafficking |
| CLTC | Clathrin heavy chain, involved in vesicle formation for cargo transport | Essential for endocytosis |
| AP2M1 | AP-2 complex subunit, cargo receptor for endocytosis | Studied in clathrin-mediated endocytosis |
| RAB7A | Rab GTPase regulating endosomal transport of cargo | Implicated in Charcot-Marie-Tooth disease |
How Is cargo receptor complex Regulated?
Cargo receptor complex activity is regulated by various mechanisms, including post-translational modifications, such as phosphorylation and ubiquitination, which can alter cargo binding or complex assembly [1, 8]. For example, phosphorylation of NDP52 modulates its ability to recruit the ULK complex during xenophagy. Additionally, the availability of specific lipids, such as phosphoinositides, can influence membrane recruitment of cargo receptors [5, 7]. The expression levels of cargo receptor genes are also subject to transcriptional and post-transcriptional control, allowing cells to adapt to changing conditions [1, 3].
cargo receptor complex and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| NCOA4 | Ferritinophagy dysregulation; cancer and neurodegeneration | Knockout cell lines to study iron homeostasis |
| VPS35 | Parkinson's disease | Knock-in mouse models of VPS35 mutations |
| CALCOCO2 (NDP52) | Xenophagy defects; increased susceptibility to infection | Knockout macrophages to assess bacterial clearance |
| SQSTM1 (p62) | Protein aggregation diseases; Paget's disease of bone | Knockout mice to study autophagy and bone metabolism |
| OPTN | Glaucoma and ALS | Patient-derived iPSCs with OPTN mutations |
Cargo Receptor Complexes in Cancer
Dysregulation of cargo receptor complexes can contribute to cancer by altering the trafficking of growth factor receptors and other signaling molecules. For instance, NCOA4-mediated ferritinophagy affects iron availability, which is critical for cancer cell proliferation. Mutations in cargo receptor genes may lead to aberrant signaling and tumor progression.
Cargo Receptor Complexes in Neurodegeneration
Defects in cargo receptor complexes are implicated in neurodegenerative diseases. For example, mutations in VPS35, a component of the retromer cargo receptor complex, are associated with Parkinson's disease. Similarly, impaired selective autophagy due to dysfunctional cargo receptors like p62 and OPTN contributes to the accumulation of protein aggregates in ALS and other neurodegenerative disorders.
Cargo Receptor Complexes in Infectious Diseases
Cargo receptor complexes play a role in host defense against pathogens. NDP52 recognizes cytosol-invading bacteria and targets them for autophagy, and pathogens may evade this defense by interfering with cargo receptor function. Understanding these interactions can inform the development of new antimicrobial strategies.
Cargo Receptor Complexes as Therapeutic Targets
Cargo receptor complexes are being explored as therapeutic targets for brain drug delivery. Receptor-mediated transcytosis, which relies on cargo receptor complexes at the blood-brain barrier, can be harnessed to deliver therapeutics to the brain. Modulating cargo receptor activity may also be beneficial in diseases characterized by protein trafficking defects.
From cargo receptor complex-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of WDR11 affect cargo transport? | WDR11 knockout cell line |
| Does NCOA4 point mutation impair ferritin binding? | NCOA4 point-mutant knock-in cells |
| Can we tag NDP52 to track its localization? | NDP52 knock-in with fluorescent tag |
| Does overexpression of p62 enhance autophagy? | p62 overexpression cell line |
| What is the role of VPS35 in endosomal sorting? | VPS35 knockout or knockdown cells |
| Can we screen for regulators of cargo receptor function? | CRISPR library screening in reporter cells [1, 8] |
How to Study the cargo receptor complex Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Affinity purification-mass spectrometry | Protein interactions and complex composition | Identifying subunits of cargo receptor complexes |
| Live-cell fluorescence imaging | Localization and dynamics of cargo receptors | Tracking cargo transport in real time [1, 5] |
| Western blotting | Cargo degradation or processing | Measuring ferritinophagy |
| CRISPR knockout screens | Genes required for cargo receptor function | Discovering regulators of selective autophagy [3, 8] |
| Proximity ligation assay | Protein-protein interactions in situ | Detecting cargo-receptor binding |
| RNA-seq | Transcriptional changes upon cargo receptor perturbation | Identifying downstream pathways |
| Immunofluorescence | Subcellular localization of cargo receptors | Visualizing complex assembly at membranes [5, 8] |
| Bacterial clearance assay | Xenophagy activity | Assessing NDP52 function |
Proteomic Identification of Cargo Receptor Complexes
Quantitative proteomics can identify components of cargo receptor complexes and their interacting partners. For example, Mancias et al. used quantitative proteomics to identify NCOA4 as the cargo receptor for ferritinophagy. Affinity purification coupled with mass spectrometry is a powerful approach to isolate and characterize these complexes.
Imaging Cargo Receptor Complex Dynamics
Live-cell imaging with fluorescently tagged cargo receptors allows visualization of their trafficking and cargo binding in real time. This can reveal the spatiotemporal dynamics of complex assembly and cargo release [1, 5]. Super-resolution microscopy can provide detailed views of complex organization at membranes.
Functional Assays for Cargo Transport
Functional assays, such as cargo degradation or recycling assays, measure the activity of cargo receptor complexes. For instance, ferritinophagy can be monitored by ferritin degradation using western blotting. Xenophagy can be assessed by bacterial clearance assays.
CRISPR Screening to Identify Regulators
Genome-wide CRISPR screens can identify genes that regulate cargo receptor complex function. For example, a screen for regulators of ferritinophagy could use a fluorescent ferritin reporter. Such screens can uncover novel components and pathways.
How CRISPR Can Be Used to Study GO:0062137 cargo receptor complex
Knockout
CRISPR knockout of cargo receptor genes, such as WDR11 or NCOA4, allows researchers to study loss-of-function phenotypes. For example, WDR11 knockout cells can reveal defects in Golgi-to-endosome transport. NCOA4 knockout cells show impaired ferritinophagy and altered iron homeostasis.
Point Mutation
Introducing point mutations into cargo receptor genes can dissect specific residues required for cargo binding or complex assembly. For instance, mutating the acidic-cluster-binding domain of WDR11 can test its role in cargo recognition. Point mutations in NCOA4 can identify residues critical for ferritin binding.
Knock-in
Knock-in of tagged versions of cargo receptors (e.g., GFP or HA) enables visualization and purification of the complex. This approach can be used to track NDP52 localization during bacterial infection. Knock-in of disease-associated mutations can model their effects in isogenic cells.
Overexpression
Overexpression of cargo receptors can enhance or saturate transport pathways. For example, overexpressing p62 can increase autophagic flux. Overexpression of WDR11 may amplify cargo transport and reveal rate-limiting steps.
How EDITGENE Supports cargo receptor complex Research
Researchers studying cargo receptor complex-related genes often need to determine whether a candidate gene is causally involved in cargo recognition, transport, or disease. EDITGENE provides a comprehensive suite of CRISPR services to enable such investigations, from gene knockout to precise point mutations and library screening.
Contact EDITGENE today to design your custom CRISPR model for cargo receptor complex research.
Frequently Asked Questions About cargo receptor complex
What is a cargo receptor complex?
A cargo receptor complex is a protein complex that is part of a membrane and functions as a cargo receptor, binding specific cargo proteins and mediating their transport, sorting, or degradation [QuickGO].
What genes are involved in cargo receptor complexes?
Key genes include WDR11, NCOA4, CALCOCO2 (NDP52), SQSTM1 (p62), OPTN, and VPS35, among others [1, 3, 7, 8].
What is the function of GO:0062137?
GO:0062137 describes the cellular component function of cargo receptor complexes, which is to recognize and transport cargo proteins across membranes [QuickGO].
How are cargo receptor complexes regulated?
They are regulated by post-translational modifications, lipid interactions, and protein expression levels [1, 5, 8].
What diseases are associated with cargo receptor complexes?
Dysregulation is linked to cancer, neurodegeneration (e.g., Parkinson's disease, ALS), and infectious diseases [3, 6, 7, 8].
What methods are used to study cargo receptor complexes?
Common methods include affinity purification-mass spectrometry, live-cell imaging, CRISPR screens, and functional assays like ferritinophagy [1, 3, 8].
Can CRISPR be used to study cargo receptor complexes?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models are widely used to dissect cargo receptor function [1, 3, 8].
What is the WDR11 complex?
The WDR11 complex is a cargo receptor complex that recognizes acidic-cluster-containing cargo proteins and mediates their transport.
How does NCOA4 function as a cargo receptor?
NCOA4 binds ferritin and delivers it to autophagosomes for degradation, a process called ferritinophagy.
What is the role of NDP52 in autophagy?
NDP52 is a cargo receptor that recruits the ULK complex to cytosol-invading bacteria, initiating selective autophagy.
Conclusion
Cargo receptor complexes (GO:0062137) are essential membrane-associated protein assemblies that recognize and transport specific cargo, playing critical roles in cellular trafficking, autophagy, and disease. Understanding their components, mechanisms, and regulation offers insights into fundamental cell biology and provides opportunities for therapeutic intervention. CRISPR-based models are invaluable tools for dissecting these complexes and their roles in health and disease.
References
- 1. Deng H et al.. 2024. The WDR11 complex is a receptor for acidic-cluster-containing cargo proteins.. Cell 187(16):4272-4288.e20 PMID: 39013469
- 3. Mancias JD et al.. 2014. Quantitative proteomics identifies NCOA4 as the cargo receptor mediating ferritinophagy.. Nature 509(7498):105-9 PMID: 24695223
- 4. Haqqani AS et al.. 2024. Receptor-mediated transcytosis for brain delivery of therapeutics: receptor classes and criteria.. Front Drug Deliv 4:1360302 PMID: 40836978
- 5. Scott CC et al.. 2014. Endosome maturation, transport and functions.. Semin Cell Dev Biol 31:2-10 PMID: 24709024
- 6. Khursigara MR et al.. 2026. A cargo receptor entrapment complex is a therapeutic node for genetically and clinically distinct proteinopathies.. bioRxiv PMID: 42523240
- 7. Cullen PJ et al.. 2018. To degrade or not to degrade: mechanisms and significance of endocytic recycling.. Nat Rev Mol Cell Biol 19(11):679-696 PMID: 30194414
- 8. Ravenhill BJ et al.. 2019. The Cargo Receptor NDP52 Initiates Selective Autophagy by Recruiting the ULK Complex to Cytosol-Invading Bacteria.. Mol Cell 74(2):320-329.e6 PMID: 30853402
