heme transmembrane transport

Definition

Target type: biologicalprocess

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. [GOC:bf]

Heme transmembrane transport is a crucial process for maintaining cellular heme homeostasis and is essential for various physiological functions. Heme, a porphyrin ring complex containing ferrous iron, plays a vital role in oxygen transport, electron transfer, and enzymatic catalysis.

The transport of heme across cellular membranes is mediated by specific transmembrane proteins, known as heme transporters. These proteins are highly conserved across different organisms and exhibit diverse mechanisms of action.

**1. ABC Transporters:**
* ABC (ATP-binding cassette) transporters are a large family of transmembrane proteins that utilize ATP hydrolysis to transport various substrates across membranes.
* Several ABC transporters have been identified to be involved in heme transport, including ABCG2 (also known as BCRP), ABCB6, and ABCB7.
* These transporters are involved in the efflux of heme from cells, contributing to heme homeostasis and preventing accumulation of toxic levels of heme.

**2. HRG1 (Heme Responsive Gene 1):**
* HRG1 is a transmembrane protein that facilitates the influx of heme into cells.
* It belongs to the major facilitator superfamily (MFS) of transporters.
* HRG1 plays a significant role in heme uptake by erythroid cells, which are responsible for red blood cell production.

**3. FLVCR1 (Feline Leukemia Virus C Receptor 1):**
* FLVCR1 is a transmembrane protein that acts as a heme exporter, transporting heme from cells.
* It is involved in heme export from various cell types, including erythroid cells, macrophages, and hepatocytes.
* FLVCR1 plays a crucial role in regulating intracellular heme levels and preventing heme accumulation.

**4. Other Transporters:**
* Other proteins, such as the mitochondrial heme transporter (MTH), are involved in the specific transport of heme across mitochondrial membranes.
* MTH is crucial for delivering heme to the mitochondrial heme biosynthesis pathway.

**Mechanism of Heme Transport:**
* The exact mechanisms of heme transport by different transporters vary depending on the specific protein.
* Some transporters, like ABCG2, utilize ATP hydrolysis to actively transport heme across membranes.
* Other transporters, like HRG1, may rely on concentration gradients or other cellular signaling pathways to facilitate heme transport.

**Regulation of Heme Transport:**
* Heme transport is tightly regulated to maintain cellular heme homeostasis.
* Factors like cellular heme levels, oxygen availability, and specific cellular signals influence the expression and activity of heme transporters.
* Dysregulation of heme transport can lead to various pathological conditions, such as anemia, porphyrias, and cancer.

**Conclusion:**
* Heme transmembrane transport is a complex process involving multiple proteins with diverse mechanisms of action.
* These transporters play crucial roles in maintaining cellular heme homeostasis and supporting various physiological functions.
* Understanding the mechanisms of heme transport is essential for developing therapeutic strategies for diseases related to heme metabolism.'
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Proteins (1)

Compounds (7)