GO:0035351 heme transmembrane transport: Mechanism, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0035351 (heme transmembrane transport) describes the movement of heme, an iron-porphyrin compound, across biological membranes via transporters or pores.
• Heme transport is essential for cytochrome c biogenesis, iron acquisition, and redox homeostasis in bacteria, parasites, and eukaryotes [1,4,7].
• Key protein families include CcsBA/CcmCD in bacteria, LHR1 in Leishmania, and putative heme carriers in mitochondria [4,5,8].
• Dysregulated heme transport contributes to virulence in Leishmania amazonensis and may influence airway epithelial responses in cystic fibrosis [5,6].
• CRISPR knockout, point mutation, knock-in, and overexpression models enable causal testing of heme transport genes in disease contexts [5,6].
• Research methods include cryo-EM, biochemical mapping, gene expression profiling, and functional transport assays [4,6,8].
Description
Heme transmembrane transport (GO:0035351) is the biological process by which heme, a compound of iron complexed in a porphyrin ring, is moved from one side of a membrane to the other by a transporter or pore. This process is fundamental to life because heme serves as a prosthetic group for cytochromes, catalases, and peroxidases, and is required for electron transport, oxygen sensing, and iron homeostasis [1,7]. In bacteria, dedicated heme delivery systems ensure that heme reaches the periplasm and cytochrome c biogenesis machinery [1,8]. In eukaryotes, heme transport across organellar membranes is critical for mitochondrial function and for pathogens that scavenge host heme. Researchers study GO:0035351 to understand how cells acquire and distribute heme, how pathogens exploit heme for virulence, and how defects in heme trafficking contribute to disease [5,6]. The process is also a target for antimicrobial and antiparasitic drug development, as blocking heme uptake can starve or intoxicate pathogens [5,7].
heme transmembrane transport At A Glance
| GO ID | GO:0035351 |
|---|---|
| GO term | heme transmembrane transport |
| Ontology | biological_process |
| Synonym | heme membrane transport |
| Major function | Translocation of heme across biological membranes |
| Definition source | QuickGO |
| Related processes | Cytochrome c biogenesis, iron acquisition, heme homeostasis |
| Key protein families | CcsBA, CcmCD, LHR1, putative mitochondrial heme carriers |
What Is GO:0035351?
According to the Gene Ontology, GO:0035351 heme transmembrane transport is defined as the process in which heme, any compound of iron complexed in a porphyrin (tetrapyrrole) ring, is transported from one side of a membrane to the other by means of some agent such as a transporter or pore. The synonym heme membrane transport is also used. This term encompasses both ATP-dependent and ATP-independent transport mechanisms, as well as transport mediated by dedicated protein channels or carriers [1,4,8].
Why Is heme transmembrane transport Important in Cell Biology?
Heme transmembrane transport is essential for cellular iron utilization, respiratory chain assembly, and redox signaling [1,7]. Defects in heme trafficking can impair cytochrome c biogenesis and mitochondrial function, while pathogens rely on heme uptake for virulence [4,5,8]. Understanding this process informs antimicrobial strategies, iron metabolism research, and the pathophysiology of diseases linked to heme dysregulation [5,6,7].
• Required for cytochrome c biogenesis in bacteria and mitochondria [1,4].
• Enables iron acquisition from host heme in pathogenic organisms [5,7].
• Supports mitochondrial electron transport and energy metabolism.
• Contributes to virulence in Leishmania amazonensis.
• May influence airway epithelial responses in cystic fibrosis.
• Target for novel antibiotics and antiparasitics [5,7].
• Linked to iron homeostasis and oxidative stress [2,3].
• Involved in heme sensing and signaling pathways.
• Provides a model for membrane protein transport mechanisms [4,8].
• Facilitates comparative studies across prokaryotes and eukaryotes [1,8].
What Happens During heme transmembrane transport?
Heme recognition and binding
In simple terms: The transporter first grabs heme on one side of the membrane.
Dedicated heme transporters such as CcsBA and CcmCD recognize heme via conserved histidine and tyrosine residues, forming a binding pocket that coordinates the iron-porphyrin ring [4,8]. In Escherichia coli, outer membrane receptors like HasR bind host hemoproteins and extract heme for internalization. This initial binding step ensures substrate specificity and prevents nonspecific membrane permeation.
Membrane translocation
In simple terms: The transporter moves heme through the membrane to the other side.
Cryo-EM structures of CcsBA reveal a transmembrane channel that undergoes conformational changes to shuttle heme across the lipid bilayer. Biochemical mapping of CcmCD in System I cytochrome c biogenesis shows a conserved heme transport mechanism involving transient heme coordination. In Leishmania, LHR1 mediates heme uptake across the plasma membrane, and its transport capacity determines virulence.
Heme release and delivery
In simple terms: Once across, heme is handed off to target proteins.
After translocation, heme is delivered to cytochrome c maturation machinery or to mitochondrial targets [1,4]. In bacteria, CcsBA releases heme to apocytochrome c, enabling covalent attachment. In eukaryotes, heme is distributed to cytochromes, catalases, and regulatory proteins.
Regulation of transport activity
In simple terms: Cells adjust heme transport based on need.
Heme transport is regulated by iron availability, heme levels, and redox status [2,7]. In E. coli, iron starvation induces heme uptake systems. In humans, NOX5 and related NADPH oxidases may influence redox-dependent heme trafficking [2,3]. Gene expression profiling in cystic fibrosis airway epithelial cells exposed to elexacaftor/tezacaftor/ivacaftor suggests modulation of heme-related pathways.
Key Genes Involved in GO:0035351 heme transmembrane transport
The following genes and proteins are experimentally implicated in heme transmembrane transport or related heme trafficking pathways.
| Gene | Major Role | Research Relevance |
|---|---|---|
| CcsBA | Heme transporter in cytochrome c biogenesis | Cryo-EM structure reveals transport mechanism |
| CcmCD | Heme transport in System I cytochrome c biogenesis | Biochemical mapping of conserved mechanism |
| LHR1 | Heme transporter in Leishmania | Virulence determinant |
| HasR | Outer membrane heme receptor in E. coli | Iron uptake from host hemoproteins |
| NOX5 | NADPH oxidase involved in redox signaling | May influence heme trafficking |
| CYBB | NADPH oxidase subunit | Conserved bis-heme motif for electron transport |
| CFTR | Chloride channel | Modulator exposure alters heme-related gene expression |
| Heme oxygenase | Heme degradation | Indirectly affects heme transport |
| Ferrochelatase | Heme biosynthesis | Provides substrate for transport |
| Mitochondrial carriers | Putative heme transport | Organellar heme distribution |
| ABC transporters | Potential heme efflux | Bacterial heme homeostasis |
| TonB system | Energy transduction for heme uptake | Iron acquisition |
| ExbBD | TonB complex component | Heme uptake energization |
| FepA | Outer membrane receptor | Heme and iron transport |
| BhuR | Heme receptor in Bordetella | Heme utilization |
| PhuR | Heme receptor in Pseudomonas | Heme uptake |
| HmuR | Heme receptor in Gram-negative bacteria | Heme transport |
How Is heme transmembrane transport Regulated?
Heme transmembrane transport is regulated at multiple levels. In bacteria, iron starvation induces the expression of heme uptake systems through Fur-regulated promoters. In Leishmania, LHR1 expression levels directly determine heme transport capacity and virulence. In human cells, redox-sensitive pathways involving NOX5 and NADPH oxidases may modulate heme trafficking [2,3]. Additionally, exposure of cystic fibrosis airway epithelial cells to elexacaftor/tezacaftor/ivacaftor alters the expression of genes related to heme and iron metabolism, suggesting pharmacological regulation.
heme transmembrane transport and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| LHR1 | Leishmaniasis virulence | Leishmania knockout |
| CFTR | Cystic fibrosis | Airway epithelial overexpression |
| NOX5 | Oxidative stress | Point mutation |
| CYBB | Chronic granulomatous disease | Knockout |
| CcsBA | Bacterial cytochrome c biogenesis | Bacterial knockout |
Leishmaniasis
LHR1-mediated heme transport is essential for Leishmania amazonensis virulence, as reduced transport capacity attenuates infection. This makes heme transport a potential drug target for leishmaniasis.
Cystic fibrosis
Gene expression profiling of CF airway epithelial cells exposed to elexacaftor/tezacaftor/ivacaftor reveals changes in heme-related pathways, suggesting that heme transport may contribute to airway biology beyond CFTR function.
Iron overload and oxidative stress
Dysregulated heme transport can lead to intracellular heme accumulation, promoting oxidative stress and tissue damage [2,3]. NOX5 and NADPH oxidases are implicated in redox-dependent heme signaling.
From heme transmembrane transport-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does LHR1 mediate heme transport? | Leishmania LHR1 knockout |
| What is the structure of CcsBA? | Cryo-EM of purified protein |
| How does CcmCD transport heme? | Biochemical mapping with mutants |
| Does CFTR modulation affect heme genes? | Airway epithelial overexpression |
| Is NOX5 involved in heme trafficking? | Point mutation |
| Can heme transport be targeted? | Knockout in bacteria |
How to Study the heme transmembrane transport Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Cryo-EM | Protein structure | CcsBA heme transport |
| Biochemical mapping | Protein interactions | CcmCD mechanism |
| RNA-seq | Gene expression | CF airway cells |
| Transport assays | Heme uptake | LHR1 virulence |
| Mutagenesis | Functional residues | CcsBA |
| Knockout models | Gene function | Leishmania |
| Overexpression | Gain of function | CFTR |
Cryo-electron microscopy
Cryo-EM has been used to determine the structure of CcsBA, revealing the basis for heme transport and cytochrome c biogenesis.
Biochemical mapping
Biochemical mapping of CcmCD in System I bacterial cytochrome c biogenesis identified a conserved heme transport mechanism.
Gene expression profiling
RNA-seq of CF airway epithelial cells exposed to elexacaftor/tezacaftor/ivacaftor revealed changes in heme-related gene expression.
Functional transport assays
Heme transport capacity of LHR1 was measured in Leishmania to determine virulence.
How CRISPR Can Be Used to Study GO:0035351 heme transmembrane transport
Knockout
CRISPR knockout of LHR1 in Leishmania amazonensis reduces heme transport capacity and attenuates virulence, providing causal evidence for its role.
Point Mutation
Point mutations in NOX5 or CYBB can disrupt redox-dependent heme trafficking and are used to study oxidative stress [2,3].
Knock-in
Knock-in of tagged CcsBA or CcmCD enables biochemical mapping and structural studies of heme transport [4,8].
Overexpression
Overexpression of CFTR in airway epithelial cells followed by elexacaftor/tezacaftor/ivacaftor treatment reveals changes in heme-related gene expression.
How EDITGENE Supports heme transmembrane transport Research
Researchers studying heme transmembrane transport-related genes often need to determine whether a candidate gene is causally involved in heme trafficking, virulence, or disease. EDITGENE provides CRISPR-based cell models and screening services to accelerate this discovery.
Contact EDITGENE today to design your custom CRISPR model for heme transmembrane transport research.
Frequently Asked Questions About heme transmembrane transport
What is heme transmembrane transport?
Heme transmembrane transport (GO:0035351) is the process of moving heme across a membrane via a transporter or pore.
What genes are involved in heme transmembrane transport?
Key genes include CcsBA, CcmCD, LHR1, HasR, and NOX5 [4,5,7,2].
Why is heme transport important for bacteria?
It enables iron acquisition and cytochrome c biogenesis [1,7].
How is heme transport studied?
Methods include cryo-EM, biochemical mapping, RNA-seq, and transport assays [4,6,8,5].
What diseases are linked to heme transport?
Leishmaniasis, cystic fibrosis, and oxidative stress-related conditions [5,6,2].
Can CRISPR be used to study heme transport?
Yes, knockout, point mutation, knock-in, and overexpression models are available [5,6,4].
What is the role of LHR1 in heme transport?
LHR1 mediates heme uptake in Leishmania and determines virulence.
How does CcsBA transport heme?
CcsBA forms a channel that shuttles heme for cytochrome c biogenesis.
Is heme transport regulated by iron?
Yes, iron starvation induces heme uptake systems in bacteria.
What are the synonyms for GO:0035351?
The synonym is heme membrane transport.
Conclusion
Heme transmembrane transport (GO:0035351) is a conserved biological process essential for iron utilization, cytochrome c biogenesis, and pathogen virulence [1,4,5,7]. Understanding its molecular mechanisms and regulation offers insights into infectious diseases, iron metabolism, and potential therapeutic targets [5,6,8]. CRISPR-based models and advanced structural methods continue to drive discoveries in this field [4,5,6].
References
- 1. Goldman BS et al.. 1998. Transmembrane heme delivery systems.. Proc Natl Acad Sci U S A 95(9):5003-8 PMID: 9560218
- 2. Touyz RM et al.. 2019. NOX5: Molecular biology and pathophysiology.. Exp Physiol 104(5):605-616 PMID: 30801870
- 3. Finegold AA et al.. 1996. Intramembrane bis-heme motif for transmembrane electron transport conserved in a yeast iron reductase and the human NADPH oxidase.. J Biol Chem 271(49):31021-4 PMID: 8940093
- 4. Mendez DL et al.. 2022. Cryo-EM of CcsBA reveals the basis for cytochrome c biogenesis and heme transport.. Nat Chem Biol 18(1):101-108 PMID: 34931065
- 5. Renberg RL et al.. 2015. The Heme Transport Capacity of LHR1 Determines the Extent of Virulence in Leishmania amazonensis.. PLoS Negl Trop Dis 9(5):e0003804 PMID: 26001191
- 6. Hampton TH et al.. 2024. Gene expression responses of CF airway epithelial cells exposed to elexacaftor/tezacaftor/ivacaftor suggest benefits beyond improved CFTR channel function.. Am J Physiol Lung Cell Mol Physiol 327(6):L905-L916 PMID: 39437760
- 7. Braun V. 2003. Iron uptake by Escherichia coli.. Front Biosci 8:s1409-21 PMID: 12957834
- 8. Kreiman AN et al.. 2025. Biochemical mapping reveals a conserved heme transport mechanism via CcmCD in System I bacterial cytochrome c biogenesis.. mBio 16(5):e0351524 PMID: 40167305
