XKR8: XK Related 8
Scramblase Involved in Phospholipid Asymmetry and Apoptosis
Gene Information Card
| Symbol | XKR8 |
|---|---|
| Full Name | XK related 8 |
| Gene Type | protein-coding |
| Chromosomal Location | 1p35.3 |
| NCBI Gene ID | 55113 ncbi.nlm.nih.gov/gene/55113 |
| Ensembl ID | ENSG00000162614 |
| UniProt ID | Q9H6D3 |
| OMIM ID | 617485 |
| HGNC ID | 29144 |
| Aliases | XRG8, XK-related protein 8, scramblase XKR8 |
Description
XKR8 (XK related 8) encodes a member of the XK family of proteins that functions as a phospholipid scramblase. It mediates the bidirectional transport of phospholipids across the plasma membrane, particularly the exposure of phosphatidylserine on the cell surface during apoptosis. This activity is essential for the recognition and clearance of apoptotic cells by phagocytes. XKR8 is activated by caspase cleavage during programmed cell death.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Cancer (various) | Dysregulation of XKR8-mediated phosphatidylserine exposure may impair apoptotic cell clearance and promote tumor immune evasion. | COSMIC; literature |
| Autoimmune disorders | Defective scramblase activity may lead to altered exposure of phosphatidylserine, affecting immune tolerance. | ClinVar; literature |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Lymph node | 12.5 | Medium |
| Spleen | 10.2 | Medium |
| Bone marrow | 8.9 | Medium |
| Thymus | 7.3 | Low |
| Lung | 4.1 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HEK293 | 15.0 | High expression |
| HeLa | 8.5 | Moderate expression |
| Jurkat | 6.2 | Low expression |
| K562 | 4.8 | Low expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1015C>T (p.Arg339Trp) | Missense | <0.01% | Unknown functional effect |
| c.1246G>A (p.Gly416Arg) | Missense | <0.01% | Unknown functional effect |
Mutation functional classification
Loss of Function (LOF)
No confirmed loss-of-function mutations reported in major databases.
Gain of Function (GOF)
No confirmed gain-of-function mutations reported.
Dominant Negative (DN)
No confirmed dominant-negative mutations reported.
View complete mutation data：
Gene Ontology (GO)
| • phospholipid scramblase activity (GO:0017127) | • apoptotic process (GO:0006915) |
| • plasma membrane (GO:0005886) | • intracellular membrane-bounded organelle (GO:0043231) |
Pathways
• Apoptosis (KEGG hsa04210)
• Phospholipid scrambling (Reactome R-HSA-1483257)
Protein Summary
XKR8 is a 660-amino acid multi-pass membrane protein localized to the plasma membrane. It contains a conserved XK domain and a C-terminal caspase cleavage site. Upon activation by caspases (e.g., caspase-3), XKR8 undergoes proteolytic cleavage, which triggers its scramblase activity, leading to rapid exposure of phosphatidylserine on the outer leaflet of the plasma membrane. This event is a key 'eat-me' signal for phagocytes during apoptosis.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| XKR8 Knockout HEK293 Cell Line | EDJ-KQ16159 | Human | 55113 | Details Get a Quote |
| XKR8 Knockout A-549 Cell Line | EDJ-KQ47347 | Human | 55113 | Details Get a Quote |
| XKR8 Knockout HCT 116 Cell Line | EDJ-KQ47348 | Human | 55113 | Details Get a Quote |
| XKR8 Knockout HeLa Cell Line | EDJ-KQ47349 | Human | 55113 | Details Get a Quote |
| XKR8 Knockout HEK293T Cell Line | EDC90235 | Human | 55113 | Details Get a Quote |
