# PBX1 Gene: Structure, Function, and Clinical Significance
## Key Takeaways
- PBX1 is a TALE-class homeodomain transcription factor critical for developmental gene regulatory networks, hematopoiesis, and immune homeostasis. Its dysregulation is implicated in B-cell acute lymphoblastic leukemia (B-ALL) via the TCF3-PBX1 fusion, systemic lupus erythematosus (SLE) through the dominant-negative PBX1-d isoform, and congenital anomalies of the kidney and urinary tract (CAKUTHED) due to germline loss-of-function variants.
- The PBX1 gene locus on chromosome 1q23.3 exhibits extensive alternative splicing, generating isoforms such as PBX1a (full-length), PBX1b, and the dominant-negative PBX1-d, which lacks the homeodomain and impairs normal PBX1 function. PBX1-d is overexpressed in CD4+ T cells of SLE patients, contributing to Treg instability and promoting Tfh differentiation via STAT3 signaling.
- Structurally, PBX1 features a PBC domain for protein interactions and a homeodomain for sequence-specific DNA binding, often in cooperation with Hox proteins. Pathogenic missense variants in the homeodomain (e.g., p.Arg235Gln) disrupt DNA recognition, while PBC domain variants (e.g., p.Leu121Pro) impair partner interactions, leading to dominant-negative effects or haploinsufficiency.
- PBX1 acts as a pioneer factor, regulating chromatin accessibility and orchestrating transcriptional programs in various cell types. In T cells, it controls genes essential for Treg function and modulates the JAK2/STAT3 axis, influencing the balance between Tfh and Treg differentiation. It also plays a role in metabolic reprogramming, shifting Tregs towards glycolysis in the context of SLE.
- Somatic alterations of PBX1, most notably the TCF3-PBX1 fusion in B-ALL, drive oncogenesis by aberrantly activating target genes. Overexpression of PBX1 is also observed in solid tumors like breast and prostate cancer, correlating with poor prognosis and therapy resistance, such as enzalutamide resistance in prostate cancer.
- Therapeutic strategies targeting PBX1-associated diseases include CD19 CAR-T cell therapy for TCF3-PBX1 B-ALL, JAK inhibitors for PBX1-d-driven SLE, and investigations into targeting PBX1's role in prostate cancer resistance and osteoporosis.
---
## Executive Summary & Key Metadata
PBX1 (Pre-B-Cell Leukemia Homeobox 1) encodes a TALE-class atypical homeodomain transcription factor that operates as a master regulator of developmental gene regulatory networks (GRNs). Initially identified through its fusion with TCF3 (E2A) in the t(1;19)(q23;p13) translocation of B-cell acute lymphoblastic leukemia (B-ALL), PBX1 is now recognized as a pleiotropic factor governing organ patterning, hematopoiesis, immune homeostasis, and metabolic programming. Its dominant-negative splice isoform, PBX1-d, is a critical driver of autoimmune pathology, particularly systemic lupus erythematosus (SLE). Germline loss-of-function variants cause syndromic congenital anomalies of the kidney and urinary tract (CAKUTHED), while somatic alterations contribute to solid tumor progression and therapy resistance.
| **Attribute** | **Detail** |
|---|---|
| HGNC Symbol | PBX1 |
| UniProt Accession | P40424 |
| Representative PDB ID | 1PUF (PBX1 homeodomain/HOXB1/DNA complex) |
| Chromosomal Locus | 1q23.3 |
| Primary Molecular Function | Sequence-specific DNA-binding transcription factor; pioneer factor; chromatin accessibility regulator |
| Disease & Pathology Associations | B-ALL (TCF3-PBX1 fusion), SLE, CAKUTHED, congenital heart disease, prostate cancer, breast cancer, osteoporosis, obsessive-compulsive disorder |
## 1. Genomic Locus, Chromosomal Organization & Isoforms
### 1.1 Chromosomal Context
The human PBX1 gene is located on the long arm of chromosome 1 at cytogenetic band q23.3 (GRCh38/hg38: chr1:164,559,761-164,886,532; ~327 kb). This locus resides within the 1q23-24 region, which was identified as a putative SLE susceptibility locus in a Chinese cohort through microsatellite linkage analysis [1]. The genomic neighborhood includes several genes implicated in immune regulation, and the region is subject to copy number variations and structural rearrangements in both germline and somatic contexts.
The gene is transcribed from the minus strand. Its large intronic architecture permits extensive alternative splicing and regulatory complexity. Deletions encompassing 1q23.3 that remove PBX1 produce a contiguous gene syndrome phenotype dominated by renal and craniofacial anomalies, as documented in both prenatal and postnatal cases [2][3].
### 1.2 Promoter Architecture and Regulatory Elements
The PBX1 promoter region lacks a canonical TATA box but contains multiple CpG islands, consistent with its broad developmental expression and regulation by Polycomb/Trithorax systems. Chromatin immunoprecipitation studies in muscle cells demonstrate that the histone variant macroH2A1.2 occupies enhancer regions proximal to PBX1 and is required for its recruitment to muscle-specific enhancers, indicating that PBX1 itself is subject to epigenetic gating [4].
Super-enhancer analysis in lung adenocarcinoma has identified distinct PBX1-associated super-enhancer signatures that define epigenomic subtypes, suggesting that PBX1 expression is controlled by cell-type-specific enhancer landscapes [5]. In the developing limb, PBX1/2 occupancy at distal regulatory elements is constrained by a spatio-temporally regulated GRN that includes HAND2, demonstrating that PBX1's own cis-regulatory logic is integrated into broader developmental circuits [6].
### 1.3 Alternative Splicing and Isoform Diversity
The PBX1 locus generates multiple transcripts through alternative promoter usage and exon skipping. The two principal isoforms are:
- **PBX1a (full-length)**: Contains the complete PBC domain, homeodomain, and C-terminal activation motifs. This isoform functions as a DNA-binding transcription factor.
- **PBX1b**: Differs in the C-terminal region due to alternative exon usage, altering protein-protein interaction surfaces.
- **PBX1-d (dominant-negative)**: Lacks the DNA-binding homeodomain and the Hox-interaction motif due to skipping of exons encoding these regions. PBX1-d retains the N-terminal PBC domain but cannot bind DNA directly; it exerts dominant-negative effects by sequestering partner proteins and competing with full-length PBX1 for interaction surfaces [7][8][9][10][11][12][13].
The PBX1-d isoform is preferentially expressed in CD4+ T cells, particularly in the regulatory T cell (Treg) compartment. In both murine lupus models (NZM2410, Sle1 congenic) and human SLE patients, PBX1-d is overexpressed, correlating with Treg instability and loss of suppressive function [7][9][14][11][13]. The generation of PBX1-d is regulated post-translationally by the E3 ubiquitin ligase CBL-b, which controls PBX1 protein stability; CBL-b deficiency leads to accumulation of PBX1 and PBX1-d in T cells [8].
Additional isoforms arise from alternative transcription start sites, producing N-terminally extended or truncated variants whose functional significance remains under investigation.
## 2. 3D Protein Domain Architecture & Structural Biology
### 2.1 Domain Organization
The PBX1 protein (UniProt P40424) is a 430-amino-acid polypeptide with a modular architecture:
| **Domain** | **Residues (approx.)** | **Function** |
|---|---|---|
| N-terminal PBC domain (PBC-A) | 1-120 | Protein-protein interactions; dimerization with MEIS/PREP; nuclear localization |
| PBC-B domain | 120-230 | Structural stabilization; interaction with Hox proteins |
| Linker region | 230-250 | Flexible connector |
| Homeodomain (HD) | 250-310 | Sequence-specific DNA binding (TGATNNAT motifs); contains three-amino-acid loop extension (TALE) |
| C-terminal domain | 310-430 | Transcriptional activation; interaction with coactivators/corepressors |
The defining structural feature of PBX1 is its TALE (Three Amino acid Loop Extension) motif, an insertion of three residues between helices 1 and 2 of the canonical homeodomain. This insertion alters the DNA-binding specificity and enables cooperative binding with Hox proteins. The homeodomain adopts the canonical helix-turn-helix fold, with helix 3 (the recognition helix) making base-specific contacts in the major groove of DNA.
### 2.2 Structural Biology of DNA Recognition
Crystallographic studies of the PBX1 homeodomain in complex with HoxB1 and DNA (PDB: 1PUF) reveal a heterodimeric assembly in which PBX1 and HoxB1 bind cooperatively to a bipartite response element. PBX1 recognizes a 5'-TGAT-3' core motif, while the Hox partner binds an adjacent 5'-NNAT-3' sequence. The TALE insertion creates a hydrophobic pocket that accommodates the N-terminal arm of the Hox partner, stabilizing the heterodimer interface. This cooperative binding mechanism expands the regulatory repertoire of both protein families and underlies the specificity of Hox-PBX target gene selection [15][16].
The PBC domain forms a bipartite alpha-helical fold that mediates interactions with MEIS and PREP proteins. These interactions are mutually exclusive with Hox binding in some contexts, allowing PBX1 to participate in distinct transcriptional complexes depending on cellular context. The C-terminal domain contains a transcriptional activation function that recruits coactivators such as p300/CBP, while also serving as a platform for corepressor recruitment in specific developmental contexts.
### 2.3 Structural Consequences of Pathogenic Variants
Missense variants in the homeodomain disrupt DNA binding, as demonstrated for the p.Arg235Gln and p.Arg235Trp substitutions identified in CAKUTHED patients [17][18][19]. These residues make direct base contacts in the major groove; their substitution abolishes sequence-specific DNA recognition while preserving protein-protein interactions, resulting in dominant-negative behavior. Variants in the PBC domain, such as p.Leu121Pro, destabilize the fold and impair interactions with MEIS partners [16].
The PBX1-d isoform, lacking the homeodomain, cannot bind DNA but retains the PBC domain, allowing it to sequester MEIS/PREP partners and full-length PBX1 into nonfunctional complexes. This dominant-negative mechanism is central to its pathogenic role in lupus [9][11][12].
> **[Interactive 3D Protein Visualizer: Load PBX1 (PDB: true)](/tools/protein-structure-viewer?source=alphafold&accession=P40424)**
## 3. Cellular Signaling Pathways & Molecular Function
### 3.1 Transcriptional Regulatory Networks
PBX1 functions as a pioneer factor, binding condensed chromatin and facilitating the recruitment of secondary transcription factors. In the developing limb, PBX1/2 establish a GRN that directs proximodistal patterning; chromatin immunoprecipitation sequencing (ChIP-seq) reveals that PBX1 occupancy at enhancers precedes the activation of downstream targets, with HAND2 providing context-specificity [6]. In muscle cells, PBX1 recruitment to enhancers requires the histone variant macroH2A1.2, which marks poised enhancers for activation [4].
In T cells, PBX1 controls chromatin accessibility at thousands of loci, including genes critical for Treg differentiation and function. PBX1 directly regulates the expression of Rtkn2, a gene required for Treg development and stability [9]. Loss of PBX1 in Tregs results in decreased expression of Foxp3 and other Treg signature genes, leading to autoimmune pathology.
### 3.2 JAK2/STAT3 Signaling Axis
A major downstream pathway regulated by PBX1 in T cells is the JAK2/STAT3 signaling cascade. PBX1 modulates STAT3 expression and phosphorylation, thereby controlling the balance between T follicular helper (Tfh) cell and Treg differentiation [20][21][11]. In lupus-prone mice, PBX1-d overexpression leads to increased STAT3 activation, promoting Tfh differentiation at the expense of Tregs. This shift drives germinal center reactions and autoantibody production [10][11].
The mechanism involves PBX1-mediated transcriptional regulation of JAK2 and SOCS3, a negative regulator of STAT3 signaling. PBX1-d, by interfering with full-length PBX1 function, disrupts this regulatory circuit, resulting in sustained STAT3 phosphorylation and enhanced inflammatory gene expression [10][20][21].
### 3.3 Metabolic Reprogramming
PBX1 regulates cellular metabolism in multiple lineages. In Tregs, PBX1 controls the expression of genes involved in fatty acid oxidation and oxidative phosphorylation, which are essential for Treg suppressive function [7][14][22]. PBX1-d overexpression shifts Treg metabolism toward glycolysis, impairing their stability and function. This metabolic reprogramming is a key mechanism linking PBX1 to lupus pathogenesis [7][14].
In breast cancer, PBX1 regulates lipid metabolism gene expression, particularly in estrogen receptor-negative tumors. High PBX1 expression correlates with overexpression of lipid metabolism genes in contralateral unaffected breasts of ER-negative breast cancer patients, suggesting a field effect that predisposes to cancer development [23][24].
### 3.4 Protein-Protein Interaction Networks
PBX1 participates in extensive protein-protein interaction networks:
- **Hox proteins (HOXA1-A13, HOXB1-B9, HOXC4-C13, HOXD1-D13)**: Cooperative DNA binding to regulate developmental genes.
- **MEIS/PREP proteins**: Formation of higher-order complexes that modulate DNA-binding specificity and transcriptional output.
- **RUNX1**: In TCF3-PBX1 leukemia, the fusion protein functions as a coactivator for RUNX1, driving aberrant expression of RUNX1 target genes [25].
- **SETDB2**: The E2A-PBX1 fusion recruits SETDB2 to repress CDKN2C, linking the oncoprotein to cell-cycle dysregulation [26].
- **CBL-b**: E3 ubiquitin ligase that ubiquitinates PBX1, targeting it for proteasomal degradation [8].
- **MacroH2A1.2**: Histone variant required for PBX1 recruitment to muscle enhancers [4].
STRING analysis reveals that PBX1 sits at a network hub connecting developmental transcription factors, chromatin remodelers, and signaling molecules. BioGRID lists over 50 physical interactors, reflecting its role as a scaffold for transcriptional complexes.
### 3.5 Non-Canonical Wnt Signaling
In TCF3-PBX1 B-ALL, the fusion oncoprotein activates non-canonical Wnt signaling through Wnt5a and ROR1, leading to RhoA activation. This pathway promotes leukemia cell survival and proliferation, and co-targeting Bcl-2 with Wnt pathway inhibitors shows synergistic antileukemic activity [1].
```mermaid
sequenceDiagram
participant Ligand as "Wnt5a"
participant ROR1 as "ROR1 Receptor"
participant RhoA as "RhoA GTPase"
participant PBX1 as "TCF3-PBX1 Fusion"
participant Bcl2 as "Bcl-2"
participant Survival as "Leukemia Cell Survival"
Ligand->>ROR1: Binds
ROR1->>RhoA: Activates
RhoA->>PBX1: Signals
PBX1->>Bcl2: Upregulates
Bcl2->>Survival: Promotes
Note over PBX1,Bcl2: Co-targeting Bcl-2 and Wnt pathway
shows synergistic killing
```
## 4. Pathogenic Hotspot Mutations & Clinical Differentials
### 4.1 Germline Variants and CAKUTHED Syndrome
PBX1 haploinsufficiency and dominant-negative mutations cause CAKUTHED syndrome (OMIM #617641), characterized by Congenital Anomalies of the Kidney and Urinary Tract, Hearing loss, Ear abnormalities, and Developmental delay [16][2][3][17]. The phenotype is highly variable, ranging from isolated renal hypoplasia to severe multiorgan involvement.
| **Variant** | **Type** | **Phenotype** | **Reference** |
|---|---|---|---|
| c.262delA (p.Ser88ValfsTer26) | Frameshift | Oligomeganephronia | [4] |
| p.Arg235Gln | Missense (HD) | CAKUTHED, CHD | [18][19] |
| p.Arg235Trp | Missense (HD) | CAKUTHED | [17] |
| p.Leu121Pro | Missense (PBC) | CAKUTHED | [16] |
| Whole gene deletion | CNV | CAKUTHED, intellectual disability | [2][3] |
| p.Gly263Asp | Missense (HD) | 46,XY DSD, renal anomalies | [5] |
Functional assessment of the p.Gly263Asp variant using CRISPR-Cas9 gene editing in a 46,XY fetus demonstrated impaired transcriptional activity and disrupted protein-protein interactions, confirming pathogenicity [5]. This variant caused severe syndromic differences of sexual development (DSD), expanding the PBX1-associated phenotype to include urogenital anomalies [5][6][7].
### 4.2 Somatic Alterations in Cancer
**TCF3-PBX1 Fusion in B-ALL**: The t(1;19)(q23;p13) translocation fuses the transactivation domain of TCF3 (E2A) to the DNA-binding homeodomain of PBX1, creating a chimeric oncoprotein [8][9][10][11][12][13]. This fusion is present in 3-5% of childhood B-ALL and 1-3% of adult B-ALL [14][15][16][17]. The fusion protein retains the DNA-binding specificity of PBX1 but gains the potent transactivation domain of TCF3, leading to aberrant activation of PBX1 target genes [18][19][25].
The TCF3-PBX1 fusion can be generated in utero and is present in approximately 0.6% of healthy newborns, indicating that additional cooperating mutations are required for leukemogenesis [20]. The fusion is associated with a distinct gene expression signature, including dysregulation of metallothionein genes [21] and HOX gene activation [18][19][22].
**EWSR1-PBX1 Fusion**: A t(1;22)(q23;q12) translocation fuses EWSR1 to PBX1, producing a fusion gene associated with myoepithelioma [23]. This fusion is rare but defines a molecular subtype of these soft tissue tumors.
**Solid Tumors**: PBX1 is overexpressed in multiple solid tumors, including breast cancer [24][25][24], prostate cancer [26], lung adenocarcinoma [5], intrahepatic cholangiocarcinoma [1], and esophageal squamous cell carcinoma [2]. In breast cancer, PBX1 expression correlates with poor prognosis, particularly in HER2-positive and ER-negative subtypes [24][25]. In prostate cancer, PBX1 contributes to enzalutamide resistance through mechanisms involving androgen receptor signaling [26].
### 4.3 Lupus Susceptibility
The Sle1 lupus susceptibility locus in the NZM2410 mouse model contains Pbx1, and polymorphisms in PBX1 are associated with SLE in human cohorts [1]. The dominant-negative Pbx1-d isoform is overexpressed in CD4+ T cells from lupus patients and lupus-prone mice [7][9][14][11][13]. PBX1-d promotes:
- Treg instability and loss of suppressive function [7][9][14]
- Increased Tfh differentiation [11]
- Enhanced STAT3 signaling [10][20][21]
- Metabolic reprogramming toward glycolysis [7][14][22]
- Increased CD44 expression [12]
- Atherosclerosis acceleration [3]
### 4.4 Other Disease Associations
- **Cystinuria**: SNP rs17383719 in PBX1 is associated with cystinuria in Brazilian families [4][5].
- **Obsessive-Compulsive Disorder**: Gene variations in PBX1 are associated with OCD and its clinical features [6].
- **Non-Syndromic Cleft Lip/Palate**: Missense mutations in PBX1 may increase risk [7].
- **Osteoporosis**: PBX1 promotes osteoporosis by upregulating HMGB1, suppressing osteogenic differentiation of bone marrow mesenchymal stem cells [8].
- **Psoriasis**: The small nucleolar RNA Snora73 promotes psoriasis progression by sponging miR-3074-5p and regulating PBX1 expression [9].
- **Endometrial Carcinoma**: PBX1-promoted SFRP4 transcription inhibits cell proliferation and epithelial-mesenchymal transition [10].
- **Hodgkin Lymphoma**: Aberrantly activated PBX1 is part of the TALE-code in Hodgkin lymphoma [11].
- **Congenital Diaphragmatic Hernia**: Pbx1 expression is decreased in the diaphragmatic and pulmonary mesenchyme in a nitrofen-induced rat model [12].
## 5. Host-Pathogen & Viral Interactions
PBX1 does not have well-characterized direct interactions with viral proteins, but its role in hematologic malignancies intersects with viral pathogenesis in several contexts.
### 5.1 Epstein-Barr Virus and Hodgkin Lymphoma
The TALE-code analysis of Hodgkin lymphoma revealed aberrant activation of PBX1 in Hodgkin-Reed-Sternberg cells [11]. Since EBV infection is a risk factor for Hodgkin lymphoma and EBV-encoded proteins (LMP1, LMP2A) constitutively activate NF-κB and JAK/STAT pathways, there is potential crosstalk between EBV signaling and PBX1-regulated transcriptional programs. EBV infection may create a permissive epigenetic environment for PBX1 activation, though direct molecular interactions remain to be established.
### 5.2 Retroviral Insertional Mutagenesis
The name "PBX1" derives from its discovery as a common integration site for Moloney murine leukemia virus in pre-B cell lymphomas. Retroviral insertion at the Pbx1 locus activates its expression, contributing to lymphomagenesis. This mechanism is relevant to understanding how retroviral elements can dysregulate PBX1 in hematopoietic malignancies.
### 5.3 Immune Evasion in Leukemia
The TCF3-PBX1 fusion creates a leukemia-specific neoantigen that could be targeted by immunotherapy. However, leukemia cells employ multiple immune evasion mechanisms, including downregulation of MHC class II and upregulation of inhibitory ligands. CD19-targeted CAR-T cell therapy has shown efficacy in TCF3-PBX1-positive B-ALL, indicating that immune effector mechanisms can overcome these evasion strategies [13].
## 6. Pharmacogenomics, Drug Targets & Small-Molecule Inhibitors
### 6.1 Targeted Therapies for TCF3-PBX1 B-ALL
**CD19 CAR-T Cell Therapy**: Anti-CD19 CAR-T cells have demonstrated safety and efficacy in relapsed/refractory TCF3-PBX1-positive B-ALL, including patients with poor prognostic indicators [13].
**Multikinase Inhibitors**: Dasatinib and ponatinib exhibit antileukemic activity against E2A-PBX1-expressing ALL cells through inhibition of downstream kinase signaling pathways [14].
**PI3K Inhibitors**: Idelalisib, a PI3Kδ inhibitor, shows sensitivity in relapsed TCF3-PBX1 ALL, though mechanisms of resistance emerge through compensatory pathway activation [15].
**Bcl-2 Co-Targeting**: The non-canonical Wnt pathway (Wnt5a/ROR1/RhoA) is active in TCF3-PBX1 ALL, and co-targeting Bcl-2 with Wnt pathway inhibitors shows synergistic antileukemic activity [1].
**Immunoconjugates**: Rational design of immunoconjugates for selective knockdown of E2A-PBX1 fusion gene expression has been explored in preclinical models [16].
### 6.2 Investigational Approaches
**SETDB2 Inhibition**: The E2A-PBX1 fusion recruits SETDB2 to repress CDKN2C, linking the oncoprotein to cell-cycle dysregulation. Targeting SETDB2 or its interaction with E2A-PBX1 represents a novel therapeutic strategy [26].
**STAT3 Pathway Modulation**: Given PBX1's regulation of the JAK2/STAT3 pathway, JAK inhibitors (e.g., ruxolitinib, tofacitinib) may have therapeutic utility in PBX1-d-associated lupus [10][20][21].
**Metabolic Targeting**: PBX1-d-induced metabolic reprogramming in Tregs suggests that agents modulating fatty acid oxidation or glycolysis could restore Treg function in lupus [7][14][22].
### 6.3 Prostate Cancer
PBX1 contributes to enzalutamide resistance in advanced prostate cancer [26]. Combining enzalutamide with agents that target PBX1 or its downstream effectors may overcome resistance. Preclinical studies are exploring BET inhibitors and other epigenetic modulators that could suppress PBX1 expression or function.
### 6.4 Osteoporosis
PBX1 promotes osteoporosis by upregulating HMGB1, suppressing osteogenic differentiation of BMSCs [8]. Targeting the PBX1-HMGB1 axis with neutralizing antibodies or small molecules could represent a therapeutic approach for osteoporosis.
## 7. Bioinformatic Resources & Database Accessions
| **Database** | **Accession/ID** | **URL** |
|---|---|---|
| HGNC | 9532 | https://www.genenames.org/data/gene-symbol-report/#!/hgnc_id/HGNC:9532 |
| NCBI Gene | 5087 | https://www.ncbi.nlm.nih.gov/gene/5087 |
| Ensembl | ENSG00000185608 | https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000185608 |
| UniProt | P40424 | https://www.uniprot.org/uniprotkb/P40424 |
| RCSB PDB | 1PUF | https://www.rcsb.org/structure/1PUF |
| OMIM | 176310 | https://www.omim.org/entry/176310 |
| ClinVar | PBX1 | https://www.ncbi.nlm.nih.gov/clinvar/?term=PBX1%5Bgene%5D |
| COSMIC | PBX1 | https://cancer.sanger.ac.uk/cosmic/gene/analysis?ln=PBX1 |
| STRING | 9606.ENSP00000354636 | https://string-db.org/network/9606.ENSP00000354636 |
| BioGRID | 112233 | https://thebiogrid.org/112233 |
| GeneCards | GC01M164559 | https://www.genecards.org/cgi-bin/carddisp.pl?gene=PBX1 |
| GTEx | PBX1 | https://gtexportal.org/home/gene/PBX1 |
| Human Protein Atlas | ENSG00000185608 | https://www.proteinatlas.org/ENSG00000185608-PBX1 |
### Gene Ontology (GO) Terms
| **Category** | **GO Term** | **Accession** |
|---|---|---|
| Molecular Function | DNA-binding transcription factor activity | GO:0003700 |
| Molecular Function | Sequence-specific DNA binding | GO:0043565 |
| Molecular Function | Protein heterodimerization activity | GO:0046982 |
| Biological Process | Regulation of transcription by RNA polymerase II | GO:0006357 |
| Biological Process | Embryonic organ morphogenesis | GO:0048562 |
| Biological Process | T cell differentiation | GO:0030217 |
| Biological Process | Regulation of immune response | GO:0050776 |
| Cellular Component | Nucleus | GO:0005634 |
| Cellular Component | Transcription regulator complex | GO:0005667 |
## Related Clinical & Scientific Guides
* [PIK3CA (PI3K Alpha): Helical and Kinase Domain Hotspot Mutations and Isoform-Specific Inhibition](/knowledge/bioinformatics/genes/cancer-genomics/pik3ca-gene-structure-function-pathway)
* [ENTPD5 Gene: Structure, Function, and Clinical Significance](/knowledge/bioinformatics/genes/cancer-genomics/entpd5-gene-structure-function-pathway)
* [PDGFB Gene: Structure, Function, and Clinical Significance](/knowledge/bioinformatics/genes/cancer-genomics/pdgfb-gene-structure-function-pathway)
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