MIS18A
MIS18 Kinetochore Protein A
Gene Information Card
| Symbol | MIS18A |
|---|---|
| Full Name | MIS18 kinetochore protein A |
| Gene Type | protein-coding |
| Chromosomal Location | 21q22.11 |
| NCBI Gene ID | 54069 ncbi.nlm.nih.gov/gene/54069 |
| Ensembl ID | ENSG00000160255 |
| UniProt ID | Q9NYP7 |
| OMIM ID | 618810 |
| HGNC ID | 12863 |
| Aliases | C21orf45, hMis18alpha, MIS18alpha |
Description
MIS18A encodes a component of the MIS18 complex, which is essential for centromere maintenance and proper kinetochore assembly during cell division. The protein localizes to centromeres in early G1 phase and recruits the centromere-specific histone H3 variant CENP-A, ensuring accurate chromosome segregation.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Breast cancer | Overexpression of MIS18A may disrupt centromere licensing, leading to aneuploidy and tumor progression. | PMID: 25686125 |
| Colorectal cancer | MIS18A upregulation correlates with chromosomal instability and poor prognosis. | PMID: 29395074 |
| Hepatocellular carcinoma | MIS18A knockdown reduces cell proliferation and induces apoptosis in liver cancer cells. | PMID: 31065037 |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Testis | 12.3 | Medium |
| Bone marrow | 8.7 | Low |
| Lymph node | 6.5 | Low |
| Spleen | 5.2 | Low |
| Other tissues | <4.0 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HeLa | 15.2 | Cervical cancer cell line |
| HEK293 | 10.1 | Embryonic kidney cells |
| MCF7 | 8.9 | Breast cancer cell line |
| HCT116 | 7.4 | Colorectal cancer cell line |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1A>G (p.Met1?) | Missense | Rare | Potential loss of start codon, unknown significance |
| c.487C>T (p.Arg163Trp) | Missense | <0.01% | Uncertain significance, reported in ClinVar |
Mutation functional classification
Loss of Function (LOF)
Loss-of-function mutations in MIS18A impair centromere licensing, leading to mitotic defects and genomic instability.
Gain of Function (GOF)
Gain-of-function has not been clearly documented; overexpression is linked to cancer but not classified as a classic gain-of-function.
Dominant Negative (DN)
Dominant-negative effects have not been reported for MIS18A.
View complete mutation data：
Gene Ontology (GO)
| • chromosome (GO:0000775) | • kinetochore (GO:0000776) |
| • cell cycle (GO:0007049) | • cell division (GO:0051301) |
| • CENP-A containing nucleosome assembly (GO:0034080) |
Pathways
• REACT:2500257 - Cell Cycle
• Mitotic
• REACT:2500260 - M Phase
• REACT:2500262 - Mitotic Prometaphase
Protein Summary
MIS18A is a 271-amino acid protein that forms a complex with MIS18B and M18BP1. It is required for the loading of CENP-A at centromeres during early G1 phase. The protein contains a coiled-coil domain and localizes to centromeres in a cell-cycle-dependent manner. Its dysregulation is implicated in chromosomal instability and cancer.
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