Details for: AP4B1

Gene ID: 10717

Gene Type:  Protein-coding  - A gene that serves as a template for producing a messenger RNA (mRNA) molecule, which is then translated into a functional protein.

Symbol: AP4B1

Ensembl ID: ENSG00000134262

Description: adaptor related protein complex 4 subunit beta 1

Selected Context(s):  Overall

Cell Significance Landscape

Contexts:

Associated with

Significant Cells

Cell Significance Index (CSI) scores for the chosen context(s)

  • central memory CD8-positive, alpha-beta T cell CL0000907
    CSI 3.53
    rCSI 2.38%
    PRS 99.44
  • early lymphoid progenitor CL0000936
    CSI 3.48
    rCSI 3.05%
    PRS 98
  • double-positive, alpha-beta thymocyte CL0000809
    CSI 2.53
    rCSI 2.58%
    PRS 98.46
  • colon epithelial cell CL0011108
    CSI 2.45
    rCSI 2.57%
    PRS 94.99
  • lamp5 GABAergic cortical interneuron CL4023011
    CSI 2.14
    rCSI 3.59%
    PRS 89.91
  • pvalb GABAergic cortical interneuron CL4023018
    CSI 2.13
    rCSI 2.65%
    PRS 88.24
  • ependymal cell CL0000065
    CSI 2.11
    rCSI 4.29%
    PRS 84.88
  • caudal ganglionic eminence derived cortical interneuron CL4023064
    CSI 2.06
    rCSI 3.64%
    PRS 89.54
  • sst GABAergic cortical interneuron CL4023017
    CSI 1.96
    rCSI 2.53%
    PRS 90.56
  • VIP GABAergic cortical interneuron CL4023016
    CSI 1.9
    rCSI 2.27%
    PRS 89.84
  • activated CD8-positive, alpha-beta T cell, human CL0001049
    CSI 1.89
    rCSI 3.23%
    PRS 98.44
  • retinal cone cell CL0000573
    CSI 1.45
    rCSI 2.33%
    PRS 91.42
  • L2/3-6 intratelencephalic projecting glutamatergic neuron CL4023040
    CSI 1.03
    rCSI 2.5%
    PRS 88.18
  • mesenchymal cell CL0008019
    CSI 0.96
    rCSI 2.43%
    PRS 94.71
  • L5 extratelencephalic projecting glutamatergic cortical neuron CL4023041
    CSI 0.7
    rCSI 2.52%
    PRS 88.4

Cell ID: Standard Cell Ontology term used for mapping and comparing cells across experiments. Ensures consistency in analyzing cellular functions across tissues.
Fold Change: Represents the ratio of the current Cell Significance Index to the Cell Significance Index Threshold, indicating how much the gene expression has changed compared to a baseline.
Cell Significance Index: Reflects how strongly a gene is expressed in this specific cell.

Cell ID: Standard Cell Ontology term used for mapping and comparing cells across experiments. Ensures consistency in analyzing cellular functions across tissues.
Fold Change: Represents the ratio of the current Cell Significance Index to the Cell Significance Index Threshold, indicating how much the gene expression has changed compared to a baseline.
Cell Significance Index: Reflects how strongly a gene is expressed in this cell type. Calculated using techniques like effect size estimation and bootstrapping for reliability.

Cell ID: Standard Cell Ontology term used for mapping and comparing cells across experiments. Ensures consistency in analyzing cellular functions across tissues.
Fold Change: Represents the ratio of the current Cell Significance Index to the Cell Significance Index Threshold, indicating how much the gene expression has changed compared to a baseline.
Cell Significance Index: Reflects how strongly a gene is expressed in this cell type. Calculated using techniques like effect size estimation and bootstrapping for reliability.
Network Configuration

Explore relationships of the current gene. Select an Interaction Source: 'ONTOLOGY' for shared pathways (GO/Reactome) or 'STRING' for protein-protein interactions. Further refine by selecting context genes and comparing Cell Significance Index (CSI) scores between baseline and target cell types and their specific contexts.

Comma-separated if multiple.
Comma-separated if multiple.

Legend:
  • Query Gene
  • Node Color (Target Cell CSI, relative to current network):
    • Very High
    • High
    • Medium
    • Low
    • Very Low
    • CSI N/A
  • Node Size: Proportional to Target Cell CSI magnitude
  • STRING PPI Edge
  • Shared Pathway Edge (ONTOLOGY)

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Other Information

This section provides additional information about the gene, including a description generated by an AI language model and details about associated proteins.

## Summary [AP4B1](/details-gene/10717) (Adaptor Related Protein Complex 4 Subunit Beta 1) is a protein-coding gene located on chromosome 1p13.2. It encodes the beta-1 subunit of the heterotetrameric Adaptor Protein 4 (AP-4) complex, a key component of the intracellular vesicle-mediated transport machinery. The AP-4 complex is involved in sorting cargo proteins from the trans-Golgi network to the endosomal-lysosomal system ([Link](https://doi.org/10.1074/jbc.274.11.7278), [Link](https://doi.org/10.1091/mbc.10.8.2787)). **Overall**, expression data indicates that [AP4B1](/details-gene/10717) is broadly expressed but shows particularly high significance in cell types with demanding protein trafficking requirements, including lymphocytes such as [central memory CD8-positive, alpha-beta T cell](/details-cell/CL0000907) and [early lymphoid progenitor](/details-cell/CL0000936), as well as various neuronal subtypes. Mutations in [AP4B1](/details-gene/10717) are associated with a form of hereditary spastic paraplegia, underscoring its critical role in neuronal function ([Link](https://doi.org/10.1016/j.ajhg.2011.04.019)). ## Cellular Roles and Expression Landscape The expression profile of [AP4B1](/details-gene/10717) suggests a fundamental role in cellular logistics across diverse tissues, with particularly high importance in the immune and nervous systems. **Overall**, the gene exhibits its highest significance in several lymphocyte populations, including [central memory CD8-positive, alpha-beta T cell](/details-cell/CL0000907) (CSI: 3.53), [early lymphoid progenitor](/details-cell/CL0000936) (CSI: 3.48), and [double-positive, alpha-beta thymocyte](/details-cell/CL0000809) (CSI: 2.53). This is consistent with a crucial function in lymphocyte development, activation, and memory, processes that rely heavily on the precise trafficking of surface receptors and effector molecules. Concurrently, [AP4B1](/details-gene/10717) is highly significant across a range of neuronal cell types. These include multiple GABAergic cortical interneurons, such as [lamp5](/details-cell/CL4023011), [pvalb](/details-cell/CL4023018), and [sst](/details-cell/CL4023017) subtypes, as well as glutamatergic neurons like [L2/3-6 intratelencephalic projecting glutamatergic neuron](/details-cell/CL4023040). This widespread and significant expression in the central nervous system highlights its essential role in maintaining neuronal homeostasis, likely through the trafficking of proteins necessary for synaptic function and axonal integrity. The gene's broad utility is further demonstrated by its significant expression in other cell types with high secretory or metabolic activity, such as [colon epithelial cell](/details-cell/CL0011108) and [ependymal cell](/details-cell/CL0000065). ## Pathways and Molecular Function Functional annotation confirms [AP4B1](/details-gene/10717)'s role as a core component of intracellular trafficking machinery. As a subunit of the [AP-4 adaptor complex](/details-ontology/GO:0030124), its primary molecular functions include [protein binding](/details-ontology/GO:0005515) and [clathrin binding](/details-ontology/GO:0030276), which are essential for the formation of transport vesicles. The gene is integral to several key biological processes, most notably [intracellular protein transport](/details-ontology/GO:0006886) and [vesicle-mediated transport](/details-ontology/GO:0016192). Its localization is primarily associated with the [trans-Golgi network (TGN)](/details-ontology/GO:0005802) and the [cytoplasmic side of trans-Golgi network transport vesicle membrane](/details-ontology/GO:0098541). This is consistent with its function in sorting proteins at the TGN for delivery to other compartments. The Reactome pathway data further specifies its involvement in [Golgi associated vesicle biogenesis](https://reactome.org/content/detail/R-HSA-432722) and [trans-Golgi network vesicle budding](https://reactome.org/content/detail/R-HSA-199992). The gene's specific annotation for [protein localization to somatodendritic compartment](/details-ontology/GO:0061938) provides a direct molecular link to its high significance in diverse neuronal populations and the neurological defects observed in its deficiency ([Link](https://doi.org/10.1016/j.ajhg.2011.04.019)). ## Research Directions The widespread yet cell-type-specific high expression of [AP4B1](/details-gene/10717) suggests it traffics distinct, critical cargo proteins in different cellular contexts. Future research should focus on identifying these specific cargoes to elucidate its precise roles in both health and disease. **Proposed Hypotheses:** 1. Given the severe neurological phenotype associated with [AP4B1](/details-gene/10717) loss-of-function and its high expression in various neuronal subtypes, it is hypothesized that [AP4B1](/details-gene/10717) is required for the specific trafficking of transmembrane proteins, such as ion channels or adhesion molecules, that are essential for synaptic transmission, axonal transport, and long-term neuronal survival. 2. The high significance of [AP4B1](/details-gene/10717) in memory and activated T cells suggests a non-redundant role in adaptive immunity. It is hypothesized that AP-4-mediated transport is critical for the proper delivery of cytotoxic granules to the immunological synapse in CD8+ T cells or for the recycling of the T-cell receptor (TCR) complex following antigen engagement, thereby sustaining T-cell effector function and memory formation. **Experimental Approach:** To test the hypothesis regarding its role in T-cell function (Hypothesis 2), a conditional knockout mouse model could be generated where *Ap4b1* is specifically deleted in T cells (e.g., using a CD4-Cre driver). T cells isolated from these knockout mice could be compared to wild-type controls. *In vitro* assays would assess proliferation, cytokine production (IFN-gamma, IL-2), and degranulation upon TCR stimulation. Advanced imaging techniques, such as total internal reflection fluorescence (TIRF) microscopy, could be used to visualize vesicle trafficking and receptor dynamics at the immunological synapse in real-time, clarifying the precise step at which AP-4 function is required. **Therapeutic Potential:** Since known pathologies linked to [AP4B1](/details-gene/10717) are caused by loss-of-function mutations, therapeutic strategies would aim at restoring its function rather than inhibition. Its ubiquitous expression and fundamental role in a core cellular process make it a poor candidate for systemic small molecule modulation, which would likely have significant off-target effects. For the monogenic disorder associated with [AP4B1](/details-gene/10717) deficiency, gene therapy represents a more viable, albeit challenging, long-term therapeutic avenue. This approach would focus on delivering a functional copy of the gene to the affected cells, primarily neurons in the central nervous system, to correct the underlying protein trafficking defect.

Genular Protein ID: 4015777819

Symbol: AP4B1_HUMAN

Name: AP-4 adaptor complex subunit beta

UniProtKB Accession Codes:

Database IDs:

Citations:

PubMed ID: 10066790

Title: AP-4, a novel protein complex related to clathrin adaptors.

PubMed ID: 10066790

DOI: 10.1074/jbc.274.11.7278

PubMed ID: 14702039

Title: Complete sequencing and characterization of 21,243 full-length human cDNAs.

PubMed ID: 14702039

DOI: 10.1038/ng1285

PubMed ID: 16710414

Title: The DNA sequence and biological annotation of human chromosome 1.

PubMed ID: 16710414

DOI: 10.1038/nature04727

PubMed ID: 15489334

Title: The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC).

PubMed ID: 15489334

DOI: 10.1101/gr.2596504

PubMed ID: 10436028

Title: Characterization of a fourth adaptor-related protein complex.

PubMed ID: 10436028

DOI: 10.1091/mbc.10.8.2787

PubMed ID: 21620353

Title: Adaptor protein complex 4 deficiency causes severe autosomal-recessive intellectual disability, progressive spastic paraplegia, shy character, and short stature.

PubMed ID: 21620353

DOI: 10.1016/j.ajhg.2011.04.019

PubMed ID: 22472443

Title: Multivariate proteomic profiling identifies novel accessory proteins of coated vesicles.

PubMed ID: 22472443

DOI: 10.1083/jcb.201111049

PubMed ID: 23186163

Title: Toward a comprehensive characterization of a human cancer cell phosphoproteome.

PubMed ID: 23186163

DOI: 10.1021/pr300630k

PubMed ID: 26542808

Title: Bivalent motif-ear interactions mediate the association of the accessory protein tepsin with the AP-4 adaptor complex.

PubMed ID: 26542808

DOI: 10.1074/jbc.m115.683409

PubMed ID: 26756312

Title: Molecular basis for the interaction between AP4 beta4 and its accessory protein, tepsin.

PubMed ID: 26756312

DOI: 10.1111/tra.12375

Sequence Information:

  • Length: 739
  • Mass: 83260
  • Checksum: B6FC92215BDA5EDC
  • Sequence:
  • MPYLGSEDVV KELKKALCNP HIQADRLRYR NVIQRVIRYM TQGLDMSGVF MEMVKASATV 
    DIVQKKLVYL YMCTYAPLKP DLALLAINTL CKDCSDPNPM VRGLALRSMC SLRMPGVQEY 
    IQQPILNGLR DKASYVRRVA VLGCAKMHNL HGDSEVDGAL VNELYSLLRD QDPIVVVNCL 
    RSLEEILKQE GGVVINKPIA HHLLNRMSKL DQWGQAEVLN FLLRYQPRSE EELFDILNLL 
    DSFLKSSSPG VVMGATKLFL ILAKMFPHVQ TDVLVRVKGP LLAACSSESR ELCFVALCHV 
    RQILHSLPGH FSSHYKKFFC SYSEPHYIKL QKVEVLCELV NDENVQQVLE ELRGYCTDVS 
    ADFAQAAIFA IGGIARTYTD QCVQILTELL GLRQEHITTV VVQTFRDLVW LCPQCTEAVC 
    QALPGCEENI QDSEGKQALI WLLGVHGERI PNAPYVLEDF VENVKSETFP AVKMELLTAL 
    LRLFLSRPAE CQDMLGRLLY YCIEEEKDMA VRDRGLFYYR LLLVGIDEVK RILCSPKSDP 
    TLGLLEDPAE RPVNSWASDF NTLVPVYGKA HWATISKCQG AERCDPELPK TSSFAASGPL 
    IPEENKERVQ ELPDSGALML VPNRQLTADY FEKTWLSLKV AHQQVLPWRG EFHPDTLQMA 
    LQVVNIQTIA MSRAGSRPWK AYLSAQDDTG CLFLTELLLE PGNSEMQISV KQNEARTETL 
    NSFISVLETV IGTIEEIKS

Genular Protein ID: 3461124652

Symbol: B1ALD3_HUMAN

Name: N/A

UniProtKB Accession Codes:

Database IDs:

Citations:

PubMed ID: 11237011

Title: Initial sequencing and analysis of the human genome.

PubMed ID: 11237011

DOI: 10.1038/35057062

PubMed ID: 15496913

Title: Finishing the euchromatic sequence of the human genome.

PubMed ID: 15496913

DOI: 10.1038/nature03001

PubMed ID: 16710414

Title: The DNA sequence and biological annotation of human chromosome 1.

PubMed ID: 16710414

DOI: 10.1038/nature04727

PubMed ID: 23186163

Title: Toward a comprehensive characterization of a human cancer cell phosphoproteome.

PubMed ID: 23186163

Sequence Information:

  • Length: 571
  • Mass: 64575
  • Checksum: 6EA8DE1EA2452524
  • Sequence:
  • MPYLGSEDVV KELKKALCNP HIQADRLRYR NVIQRVIRMS KLDQWGQAEV LNFLLRYQPR 
    SEEELFDILN LLDSFLKSSS PGVVMGATKL FLILAKMFPH VQTDVLVRVK GPLLAACSSE 
    SRELCFVALC HVRQILHSLP GHFSSHYKKF FCSYSEPHYI KLQKVEVLCE LVNDENVQQV 
    LEELRGYCTD VSADFAQAAI FAIGGIARTY TDQCVQILTE LLGLRQEHIT TVVVQTFRDL 
    VWLCPQCTEA VCQALPGCEE NIQDSEGKQA LIWLLGVHGE RIPNAPYVLE DFVENVKSET 
    FPAVKMELLT ALLRLFLSRP AECQDMLGRL LYYCIEEEKD MAVRDRGLFY YRLLLVGIDE 
    VKRILCSPKS DPTLGLLEDP AERPVNSWAS DFNTLVPVYG KAHWATISKC QGAERCDPEL 
    PKTSSFAASG PLIPEENKER VQELPDSGAL MLVPNRQLTA DYFEKTWLSL KVAHQQVLPW 
    RGEFHPDTLQ MALQVVNIQT IAMSRAGSRP WKAYLSAQDD TGCLFLTELL LEPGNSEMQI 
    SVKQNEARTE TLNSFISVLE TVIGTIEEIK S

Genular Protein ID: 462228607

Symbol: B1ALD1_HUMAN

Name: N/A

UniProtKB Accession Codes:

Database IDs:

Citations:

PubMed ID: 11237011

Title: Initial sequencing and analysis of the human genome.

PubMed ID: 11237011

DOI: 10.1038/35057062

PubMed ID: 15496913

Title: Finishing the euchromatic sequence of the human genome.

PubMed ID: 15496913

DOI: 10.1038/nature03001

PubMed ID: 16710414

Title: The DNA sequence and biological annotation of human chromosome 1.

PubMed ID: 16710414

DOI: 10.1038/nature04727

Sequence Information:

  • Length: 664
  • Mass: 74939
  • Checksum: 0BADBD4BE80DA9D2
  • Sequence:
  • MPYLGSEDVV KELKKALCNP HIQADRLRYR NVIQRVIRMP GVQEYIQQPI LNGLRDKASY 
    VRRVAVLGCA KMHNLHGDSE VDGALVNELY SLLRDQDPIV VVNCLRSLEE ILKQEGGVVI 
    NKPIAHHLLN RMSKLDQWGQ AEVLNFLLRY QPRSEEELFD ILNLLDSFLK SSSPGVVMGA 
    TKLFLILAKM FPHVQTDVLV RVKGPLLAAC SSESRELCFV ALCHVRQILH SLPGHFSSHY 
    KKFFCSYSEP HYIKLQKVEV LCELVNDENV QQVLEELRGY CTDVSADFAQ AAIFAIGGIA 
    RTYTDQCVQI LTELLGLRQE HITTVVVQTF RDLVWLCPQC TEAVCQALPG CEENIQDSEG 
    KQALIWLLGV HGERIPNAPY VLEDFVENVK SETFPAVKME LLTALLRLFL SRPAECQDML 
    GRLLYYCIEE EKDMAVRDRG LFYYRLLLVG IDEVKRILCS PKSDPTLGLL EDPAERPVNS 
    WASDFNTLVP VYGKAHWATI SKCQGAERCD PELPKTSSFA ASGPLIPEEN KERVQELPDS 
    GALMLVPNRQ LTADYFEKTW LSLKVAHQQV LPWRGEFHPD TLQMALQVVN IQTIAMSRAG 
    SRPWKAYLSA QDDTGCLFLT ELLLEPGNSE MQISVKQNEA RTETLNSFIS VLETVIGTIE 
    EIKS

Genular Protein ID: 2128586335

Symbol: B4DTG3_HUMAN

Name: N/A

UniProtKB Accession Codes:

Database IDs:

Sequence Information:

  • Length: 640
  • Mass: 71936
  • Checksum: 29D97B77EDF9868E
  • Sequence:
  • MVRGLALRSM CSLRMPGVQE YIQQPILNGL RDKASYVRRV AVLGCAKMHN LHGDSEVDGA 
    LVNELYSLLR DQDPIVVVNC LRSLEEILKQ EGGVVINKPI AHHLLNRMSK LDQWGQAEVL 
    NFLLRYQPRS EEELFDILNL LDSFLKSSSP GVVMGATKLF LILAKMFPHV QTDVLVRVKG 
    PLLAACSSES RELCFVALCH VRQILHSLPG HFSSHYKKFF CSYSEPHYIK LQKVEVLCEL 
    VNDENVQQVL EELRGYCTDV SADFAQAAIF AIGGIARTYT DQCVQILTEL LGLRQEHITT 
    VVVQTFRDLV WLCPQCTEAV CQALPGCEEN IQDSEGKQAL IWLLGVHGER IPNAPYVLED 
    FVENVKSETF PAVKMELLTA LLRLFLSRPA ECQDMLGRLL YYCIEEEKDM AVRDRGLFYY 
    RLLLVGIDEV KRILCSPKSD PTLGLLEDPA ERPVNSWASD FNTLVPVYGK AHWATISKCQ 
    GAGRCDPELP KTSSFAASGP LIPEENKERV QELPDSGALM LVPNRQLTAD YFEKTWLSLK 
    VAHQQVLPWR GEFHPDTLQM ALQVVNIQTI AMSRAGSRPW KAYLSAQDDT GCLFLTELLL 
    EPGNSEMQIS VKQNEARTET LNSFISVLET VIGTIEEIKS

Genular Protein ID: 412319161

Symbol: B3KSJ4_HUMAN

Name: N/A

UniProtKB Accession Codes:

Database IDs:

Citations:

PubMed ID: 14702039

Title: Complete sequencing and characterization of 21,243 full-length human cDNAs.

PubMed ID: 14702039

DOI: 10.1038/ng1285

Sequence Information:

  • Length: 571
  • Mass: 64461
  • Checksum: A84C7F5FBF0394C1
  • Sequence:
  • MPYLGSEDVV KELKKALCNP HIQADRLRYR NVIQRVIRMS KLDQWGQAEV LNFLLRYQPR 
    SEEELFDILN LLDSFLKSSS PGVVMGATKL FLILAKMSPH VQTDVLVRVK GPLLAACSSE 
    SRELCFVALC HVRQILHSLP GHFSSHYKKF FCSYSEPHYI KLQKVEVLCE LVSDENVQQV 
    LEELRGYCTD VSADFAQAAI FAIGGIARTY TDQCVQILTE LLGLRQEHIT TVVVQTFRDL 
    VWLCPQCTEA VCQALPGCEE NIQDSEGKQA LIWLLGVHGE RIPNAPYVLE DFVENVKSET 
    FPAVKMELLT ASLRLFLSRP AECQDMLGRL LYYCIEEEKD MAVRDRGLFY YRLLLVGIDE 
    VKRILCSPKS DPTLGLLEDP AERPVNSWAS DFNTLVPVYG KAHWATISKC QGAERCDPEL 
    PKTSSFAASG PLIPEENKER VQELPDSGAL MLVPNRQLTA DYFEKTWLSL KVAHQQVLPW 
    RGEFHPDTLQ MALQVVNIQT IAMSRAGSRP WKAYLSAQDD TGCLFLTELL LEPGNSEMQI 
    SVKQNEARTE TLNSFISVLE TVIGTIEEIK S