BLOC1S4 Gene - Biogenesis of Lysosomal Organelles Complex 1 Subunit 4
Essential component of the BLOC-1 complex involved in lysosome-related organelle biogenesis
Gene Information Card
| Symbol | BLOC1S4 |
|---|---|
| Full Name | Biogenesis of Lysosomal Organelles Complex 1 Subunit 4 |
| Gene Type | Protein coding |
| Chromosomal Location | 4p16.1 |
| NCBI Gene ID | 55330 ncbi.nlm.nih.gov/gene/55330 |
| Ensembl ID | ENSG00000138668 |
| UniProt ID | Q9NUP1 |
| OMIM ID | 609762 |
| HGNC ID | 20992 |
| Aliases | Cappuccino homolog (mouse), CNO, BLOS4, HPS9 |
Description
BLOC1S4 encodes a subunit of the biogenesis of lysosomal organelles complex-1 (BLOC-1), which is required for the biogenesis of specialized lysosome-related organelles such as melanosomes and platelet dense granules. Mutations in this gene cause Hermansky-Pudlak syndrome type 9 (HPS9), characterized by oculocutaneous albinism and platelet storage pool deficiency.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Hermansky-Pudlak syndrome 9 (HPS9) | Loss-of-function mutations in BLOC1S4 disrupt BLOC-1 complex assembly, impairing melanosome and platelet dense granule biogenesis. | OMIM #614171; multiple affected families reported |
| Oculocutaneous albinism (OCA) | Defective melanosome formation due to BLOC-1 dysfunction leads to reduced pigmentation. | ClinVar; case studies in HPS9 patients |
| Platelet storage pool deficiency | Impaired dense granule formation in platelets causes bleeding diathesis. | ClinVar; functional studies in mouse models |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Brain | 5.2 | Low |
| Lung | 3.8 | Low |
| Liver | 2.1 | Low |
| Kidney | 4.0 | Low |
| Skin | 6.5 | Medium |
| Spleen | 3.0 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HEK293 | 4.5 | Low expression |
| HeLa | 3.2 | Low expression |
| K562 | 2.8 | Low expression |
| Melanocytes | 8.1 | Medium expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.97C>T (p.Arg33Ter) | Nonsense | <0.01% | Premature stop; loss of function |
| c.151_152delAG (p.Arg51GlufsTer12) | Frameshift | <0.01% | Frameshift; loss of function |
| c.208C>T (p.Arg70Trp) | Missense | <0.01% | Likely damaging; disrupts BLOC-1 interaction |
Mutation functional classification
Loss of Function (LOF)
Nonsense and frameshift mutations lead to truncated or absent protein, causing BLOC-1 complex instability and HPS9.
Gain of Function (GOF)
No gain-of-function mutations reported for BLOC1S4.
Dominant Negative (DN)
No dominant-negative mutations reported; HPS9 is autosomal recessive.
View complete mutation data：
Gene Ontology (GO)
| • lysosome (GO:0005764) | • BLOC-1 complex (GO:0031083) |
| • melanosome (GO:0032438) | • secretory granule (GO:0030141) |
| • protein binding (GO:0005515) |
Pathways
• Lysosome-related organelle biogenesis (BLOC-1 pathway)
• Hermansky-Pudlak syndrome pathway
Protein Summary
BLOC1S4 (UniProt Q9NUP1) is a 140-amino-acid protein that localizes to the BLOC-1 complex, which is involved in cargo sorting and vesicle trafficking to lysosome-related organelles. The protein contains a coiled-coil domain mediating interactions with other BLOC-1 subunits. Loss of BLOC1S4 leads to mislocalization of lysosomal membrane proteins and defective organelle biogenesis.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| BLOC1S4 Knockout HEK293 Cell Line | EDJ-KQ12540 | Human | 55330 | Details Get a Quote |
| BLOC1S4 Knockout A-549 Cell Line | EDJ-KQ41536 | Human | 55330 | Details Get a Quote |
| BLOC1S4 Knockout HCT 116 Cell Line | EDJ-KQ41537 | Human | 55330 | Details Get a Quote |
| BLOC1S4 Knockout HeLa Cell Line | EDJ-KQ41538 | Human | 55330 | Details Get a Quote |
