MAX (also known as myc-associated factor X) is a gene that in humans encodes the MAX transcription factor.^[5][6]

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MAX
Available structures PDB Ortholog search: PDBe RCSB List of PDB id codes 1AN2, 1HLO, 1NKP, 1NLW, 1R05
Identifiers
Aliases	MAX, bHLHd4, max, MYC associated factor X
External IDs	OMIM: 154950; MGI: 96921; HomoloGene: 1786; GeneCards: MAX; OMA:MAX - orthologs
Gene location (Human) Chr. Chromosome 14 (human)[1] Band 14q23.3 Start 65,006,174 bp[1] End 65,102,695 bp[1]
Gene location (Mouse) Chr. Chromosome 12 (mouse)[2] Band 12 C3|12 33.78 cM Start 76,984,043 bp[2] End 77,008,975 bp[2]
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in monocyte oocyte secondary oocyte blood olfactory bulb Achilles tendon nipple lactiferous duct trigeminal ganglion germinal epithelium Top expressed in lip esophagus yolk sac secondary oocyte superior frontal gyrus interventricular septum blood thymus lens left colon More reference expression data BioGPS More reference expression data
Gene ontology Molecular function sequence-specific DNA binding protein dimerization activity DNA-binding transcription factor activity transcription coactivator activity transcription coregulator activity RNA polymerase II general transcription initiation factor activity RNA polymerase II cis-regulatory region sequence-specific DNA binding protein binding DNA binding protein homodimerization activity E-box binding RNA polymerase II transcription regulatory region sequence-specific DNA binding DNA-binding transcription repressor activity, RNA polymerase II-specific DNA-binding transcription factor activity, RNA polymerase II-specific protein-containing complex binding protein heterodimerization activity Cellular component PML body cell projection dendrite nucleus nucleoplasm cytoplasm protein-DNA complex MLL1 complex RNA polymerase II transcription regulator complex Biological process neuron apoptotic process regulation of transcription, DNA-templated regulation of transcription by RNA polymerase II cellular response to starvation transcription by RNA polymerase II negative regulation of gene expression transcription, DNA-templated response to insulin cellular response to peptide hormone stimulus retina development in camera-type eye response to axon injury response to organonitrogen compound negative regulation of transcription by RNA polymerase II negative regulation of G0 to G1 transition G1/S transition of mitotic cell cycle protein-containing complex assembly positive regulation of nucleic acid-templated transcription positive regulation of transcription by RNA polymerase II Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 4149 17187 Ensembl ENSG00000125952 ENSMUSG00000059436 UniProt P61244 Q8TAX8 P28574 RefSeq (mRNA) NM_001271068 NM_001271069 NM_002382 NM_145112 NM_145113 NM_145114 NM_145116 NM_197957 NM_001320415 NM_001146176 NM_008558 NM_001361663 NM_001361664 RefSeq (protein) NP_001257997 NP_001257998 NP_001307344 NP_002373 NP_660087 NP_660088 NP_660089 NP_932061 NP_002373.3 NP_660087.1 NP_660088.1 NP_001307344.1 NP_001139648 NP_001348592 NP_001348593 NP_032584 Location (UCSC) Chr 14: 65.01 – 65.1 Mb Chr 12: 76.98 – 77.01 Mb PubMed search [3] [4]
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The protein product of MAX contains the basic helix-loop-helix and leucine zipper motifs. It is therefore included in the bHLHZ family of transcription factors. It is able to form homodimers with other MAX proteins and heterodimers with other transcription factors, including Mad, Mxl1 and Myc. The homodimers and heterodimers compete for a common DNA target site (the E-box) in a gene promoter zone. Rearrangement of dimers (e.g., Mad:Max, Max:Myc) provides a system of transcriptional regulation with greater diversity of gene targets. Max must dimerise in order to be biologically active.^[7]

Transcriptionally active hetero- and homodimers involving Max can promote cell proliferation as well as apoptosis.^[8]

The protein product of Max has been shown to interact with:

• Myc,^{[9][10][11][12][13][14][15][16][17][18][19][20][21]}
• MNT,^[18]
• MSH2,^[13]
• MXD1,^{[15][17][19][22]}
• MXI1,^{[16][18][20][23]}
• MYCL1,^[14][20]
• N-Myc,^[14][20]
• SPAG9,^[15]
• TEAD1,^[24] and
• Transformation/transcription domain-associated protein.^[10][11]

This gene has been shown mutated in cases of hereditary pheochromocytoma.^[25] More recently the Max gene becomes mutated and becomes inactivated in small cell lung cancer (SCLC). This is mutually exclusive with alterations at Myc and BRG1, the latter coding for an ATPase of the SWI/SNF complex. It was demonstrated that the BRG1 product regulates the expression of Max through direct recruitment to the Max promoter region, and that depletion of BRG1 strongly hinders cell growth, specifically in Max-deficient cells, suggesting that the two together cause synthetic lethality. Furthermore, Max required BRG1 to activate neuroendocrine transcriptional programs and to up-regulate Myc targets, such as glycolytic-related genes.^[26]