A basic helix–loop–helix (bHLH) is a

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...

structural motif In a polymer, chain-like biological molecule, such as a protein or nucleic acid, a structural motif is a common Biomolecular structure#Tertiary structure, three-dimensional structure that appears in a variety of different, evolutionarily unrel ...

that characterizes one of the largest families of dimerizing

transcription factors In molecular biology, a transcription factor (TF) (or sequence-specific DNA-binding factor) is a protein that controls the rate of transcription of genetic information from DNA to messenger RNA, by binding to a specific DNA sequence. The func ...

. The word "basic" does not refer to complexity but to the chemistry of the motif because transcription factors in general contain

basic BASIC (Beginners' All-purpose Symbolic Instruction Code) is a family of general-purpose, high-level programming languages designed for ease of use. The original version was created by John G. Kemeny and Thomas E. Kurtz at Dartmouth College ...

amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha am ...

residues in order to facilitate DNA binding. bHLH transcription factors are often important in development or cell activity. For one, BMAL1-Clock (also called

ARNTL Aryl hydrocarbon receptor nuclear translocator-like protein 1 (ARNTL) or brain and muscle ARNT-Like 1 (BMAL1) is a protein that in humans is encoded by the gene on chromosome 11, region p15.3. It's also known as ''BMAL1'', ''MOP3'', and, less com ...

) is a core transcription complex in the molecular

circadian clock A circadian clock, or circadian oscillator, is a biochemical oscillator that cycles with a stable phase (waves), phase and is synchronized with solar time. Such a clock's ''in vivo'' period is necessarily almost exactly 24 hours (the earth's curre ...

. Other genes, like

c-Myc ''Myc'' is a family of regulator genes and proto-oncogenes that code for transcription factors. The ''Myc'' family consists of three related human genes: ''c-myc'' (MYC), ''l-myc'' (MYCL), and ''n-myc'' (MYCN). ''c-myc'' (also sometimes referre ...

and

HIF-1 Hypoxia-inducible factors (HIFs) are transcription factors that respond to decreases in available oxygen in the cellular environment, or hypoxia. They are only present in parahoxozoan animals. Discovery The HIF transcriptional complex w ...

, have been linked to

cancer Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal b ...

due to their effects on cell growth and metabolism.

Structure

The motif is characterized by two

α-helices The alpha helix (α-helix) is a common motif in the secondary structure of proteins and is a right hand-helix conformation in which every backbone N−H group hydrogen bonds to the backbone C=O group of the amino acid located four residues ear ...

connected by a

loop Loop or LOOP may refer to: Brands and enterprises * Loop (mobile), a Bulgarian virtual network operator and co-founder of Loop Live * Loop, clothing, a company founded by Carlos Vasquez in the 1990s and worn by Digable Planets * Loop Mobile, an ...

. In general, transcription factors (including this type) are dimeric, each with one helix containing

residues that facilitate DNA binding. In general, one helix is smaller, and due to the flexibility of this loop, allows dimerization by folding and packing against another helix. The larger helix typically contains the DNA-binding regions. bHLH proteins typically bind to a

consensus sequence In molecular biology and bioinformatics, the consensus sequence (or canonical sequence) is the calculated order of most frequent residues, either nucleotide or amino acid, found at each position in a sequence alignment. It serves as a simplified r ...

called an

E-box An E-box (enhancer box) is a DNA response element found in some eukaryotes that acts as a protein-binding site and has been found to regulate gene expression in neurons, muscles, and other tissues. Its specific DNA sequence, CANNTG (where N can be ...

, CANNTG. The canonical

is CACGTG (

palindromic A palindrome is a word, number, phrase, or other sequence of symbols that reads the same backwards as forwards, such as the words ''madam'' or ''racecar'', the date and time ''11/11/11 11:11,'' and the sentence: "A man, a plan, a canal – Panam ...

), however some bHLH transcription factors, notably those of the bHLH- PAS family, bind to related non-palindromic sequences, which are similar to the E-box. bHLH TFs may homodimerize or heterodimerize with other bHLH TFs and form a large variety of dimers, each one with specific functions.

Examples

A phylogenetic analysis suggested that bHLH proteins fall into 6 major groups, indicated by letters A through F. Examples of transcription factors containing a bHLH include:

Group A

MyoD MyoD, also known as myoblast determination protein 1, is a protein in animals that plays a major role in regulating muscle differentiation. MyoD, which was discovered in the laboratory of Harold M. Weintraub, belongs to a family of proteins know ...

* Myf5 * Beta2/NeuroD1 * Scl, also known as

Tal1 __NOTOC__ T-cell acute lymphocytic leukemia protein 1 (i.e. TAL1 but also termed stem cell leukemia/T-cell acute leukemia 1 .e. SCL/TAL1 is a protein that in humans is encoded by the ''TAL1'' gene. The protein encoded by TAL1 is a basic helix-lo ...

* proneural bHLH genes like p-CaMKII, and . *

Neurogenins Neurogenins are a family of bHLH transcription factors involved in specifying neuronal differentiation. It is one of many gene families related to the ''atonal'' gene in Drosophila. Other positive regulators of neuronal differentiation also exp ...

Group B

* MAX *

C-Myc ''Myc'' is a family of regulator genes and proto-oncogenes that code for transcription factors. The ''Myc'' family consists of three related human genes: ''c-myc'' (MYC), ''l-myc'' (MYCL), and ''n-myc'' (MYCN). ''c-myc'' (also sometimes referre ...

N-Myc N-myc proto-oncogene protein also known as N-Myc or basic helix-loop-helix protein 37 (bHLHe37), is a protein that in humans is encoded by the ''MYCN'' gene. Function The ''MYCN'' gene is a member of the MYC family of transcription factors an ...

TCF4 Transcription factor 4 (TCF-4) also known as immunoglobulin transcription factor 2 (ITF-2) is a protein that in humans is encoded by the TCF4 gene located on chromosome 18q21.2. Function TCF4 proteins act as transcription factors which will ...

(Transcription Factor 4)

Group C

These proteins contain two additional

PAS domain A Per-Arnt-Sim (PAS) domain is a protein domain found in all kingdoms of life. Generally, the PAS domain acts as a molecular sensor, whereby small molecules and other proteins associate via binding of the PAS domain. Due to this sensing capability ...

s after the bHLH domain. *

AhR Ahr () is a river in Germany, a left tributary of the Rhine. Its source is at an elevation of approximately above sea level in Blankenheim in the Eifel, in the cellar of a timber-frame house near the castle of Blankenheim. After it crosses fro ...

* BMAL-1-

CLOCK A clock or a timepiece is a device used to measure and indicate time. The clock is one of the oldest human inventions, meeting the need to measure intervals of time shorter than the natural units such as the day, the lunar month and the ...

* HIF *

NPAS1 NPAS1 is a basic helix-loop-helix transcription factor In molecular biology, a transcription factor (TF) (or sequence-specific DNA-binding factor) is a protein that controls the rate of transcription of genetic information from DNA to mes ...

NPAS3 NPAS3 or Neuronal PAS domain protein 3 is a brain-enriched transcription factor belonging to the bHLH-PAS superfamily of transcription factors, the members of which carry out diverse functions, including circadian oscillations, neurogenesis, to ...

, MOP5

Group D

* EMC

Group E

HEY1 Hairy/enhancer-of-split related with YRPW motif protein 1 is a protein that in humans is encoded by the ''HEY1'' gene. Function This gene encodes a nuclear protein belonging to the hairy and enhancer of split-related (HESR) family of basic hel ...

and

HEY2 Hairy/enhancer-of-split related with YRPW motif protein 2 (HEY2) also known as cardiovascular helix-loop-helix factor 1 (CHF1) is a protein that in humans is encoded by the ''HEY2'' gene. This protein is a type of transcription factor that belong ...

Group F

These proteins contain an additional COE domain *

EBF1 Transcription factor COE1 is a protein that in humans is encoded by the ''EBF1'' gene. EBF1 stands for Early B-Cell Factor 1. EBF1 controls the expression of key proteins required for B cell differentiation, signal transduction and function. The ...

Regulation

Since many bHLH

are heterodimeric, their activity is often highly regulated by the dimerization of the subunits. One subunit's expression or availability is often controlled, whereas the other subunit is constitutively expressed. Many of the known regulatory proteins, such as the ''

Drosophila ''Drosophila'' () is a genus of flies, belonging to the family Drosophilidae, whose members are often called "small fruit flies" or (less frequently) pomace flies, vinegar flies, or wine flies, a reference to the characteristic of many species ...

'' extramacrochaetae protein, have the helix-loop-helix structure but lack the basic region, making them unable to bind to DNA on their own. They are, however, able to form

heterodimers In biochemistry, a protein dimer is a macromolecular complex formed by two protein monomers, or single proteins, which are usually non-covalently bound. Many macromolecules, such as proteins or nucleic acids, form dimers. The word ''dimer'' ha ...

with proteins that have the bHLH structure, and inactivate their abilities as transcription factors.

History

* 1989: Murre et al. showed that dimers of various bHLH proteins bind to a short DNA motif (later called

E-Box An E-box (enhancer box) is a DNA response element found in some eukaryotes that acts as a protein-binding site and has been found to regulate gene expression in neurons, muscles, and other tissues. Its specific DNA sequence, CANNTG (where N can be ...

). This E-box consists of the DNA sequence CANNTG, where N can be any

nucleotide Nucleotides are organic molecules consisting of a nucleoside and a phosphate. They serve as monomeric units of the nucleic acid polymers – deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), both of which are essential biomolecules wi ...

. * 1994: Harrison's and Pabo's groups crystallize bHLH proteins bound to E-boxes, demonstrating that the parallel 4-helix bundle motif loop orients the basic sequences to interact with specific nucleotides in the major groove of the E-box. * 1994: Wharton et al. identified asymmetric E-boxes bound by a subset of bHLH proteins with PAS domains (bHLH-PAS proteins), including Single-minded (Sim) and the aromatic hydrocarbon receptor. * 1995: Semenza's group identifies hypoxia-inducible factor (HIF) as a bHLH-PAS heterodimer that binds a related asymmetric E-box. * 2009: Grove, De Masi ''et al.'', identified novel short DNA motifs, bound by a subset of bHLH proteins, which they defined as "E-box-like sequences". These are in the form of CAYRMK, where Y stands for C or T, R is A or G, M is A or C and K is G or T.

Human proteins with helix–loop–helix DNA-binding domain

AHR Ahr () is a river in Germany, a left tributary of the Rhine. Its source is at an elevation of approximately above sea level in Blankenheim in the Eifel, in the cellar of a timber-frame house near the castle of Blankenheim. After it crosses fro ...

; AHRR; ARNT;

ARNT2 Aryl hydrocarbon receptor nuclear translocator 2 is a protein that in humans is encoded by the ''ARNT2'' gene In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." mea ...

;

ARNTL2 Aryl hydrocarbon receptor nuclear translocator-like 2, also known as Mop9, Bmal2, Clif, or Arntl2, is a gene. Arntl2 is a paralog to Arntl, which are both homologs of the Drosophila Cycle. Homologs were also isolated in fish, birds and mammals s ...

;

ASCL1 Achaete-scute homolog 1 is a protein that in humans is encoded by the ''ASCL1'' gene. Because it was discovered subsequent to studies on its homolog in Drosophila, the Achaete-scute complex, it was originally named MASH-1 for mammalian achaete scu ...

;

ASCL2 Achaete-scute complex homolog 2 (Drosophila), also known as ASCL2, is an imprinted human gene. Function This gene is a member of the basic helix-loop-helix (BHLH) family of transcription factors. It activates transcription by binding to the E ...

; ASCL3; ASCL4;

ATOH1 Protein atonal homolog 1 is a protein that in humans is encoded by the ''ATOH1'' gene. Function This protein belongs to the basic helix-loop-helix (BHLH) family of transcription factors. It activates E-box dependent transcription along with TC ...

; ATOH7; ATOH8;

BHLHB2 Class E basic helix-loop-helix protein 40 is a protein that in humans is encoded by the ''BHLHE40'' gene In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ...

;

BHLHB3 "Basic helix-loop-helix family, member e41", or BHLHE41, is a gene that encodes a basic helix-loop-helix transcription factor repressor protein in various tissues of both humans and mice. It is also known as DEC2, hDEC2, and SHARP1, and was previ ...

; BHLHB4; BHLHB5;

BHLHB8 Class A basic helix-loop-helix protein 15 (bHLHa15) also known as class B basic helix-loop-helix protein 8 (bHLHb8) or muscle, intestine and stomach expression 1 (MIST-1) is a protein that in humans is encoded by the BHLHA15 gene. Function bH ...

;

EPAS1 Endothelial PAS domain-containing protein 1 (EPAS1, also known as hypoxia-inducible factor-2alpha (HIF-2α)) is a protein that is encoded by the ''EPAS1'' gene in mammals. It is a type of hypoxia-inducible factor, a group of transcription factors ...

; FERD3L;

FIGLA Folliculogenesis-specific basic helix-loop-helix, also known as factor in the germline alpha (FIGalpha) or transcription factor FIGa, is a protein that in humans is encoded by the ''FIGLA'' gene. The FIGLA gene is a germ cell-specific transcriptio ...

;

HAND1 Heart- and neural crest derivatives-expressed protein 1 is a protein that in humans is encoded by the ''HAND1'' gene. A member of the HAND subclass of basic Helix-loop-helix (bHLH) transcription factors, the Heart and neural crest-derived transc ...

;

HAND2 Heart- and neural crest derivatives-expressed protein 2 is a protein that in humans is encoded by the ''HAND2'' gene. Function The protein encoded by this gene belongs to the basic helix-loop-helix family of transcription factors. This gene p ...

;

HES1 Transcription factor HES1 (hairy and enhancer of split-1) is a protein that is encoded by the ''Hes1'' gene, and is the mammalian homolog of the hairy gene in ''Drosophila.'' HES1 is one of the seven members of the Hes gene family (HES1-7). Hes ge ...

; HES2; HES3; HES4;

HES5 Transcription factor HES-5 is a protein that in humans is encoded by the ''HES5'' gene. HES5 regulates the development of the early brain by maintaining stem cell neural progenitors in the ventricular zone. HES5 expression significantly higher in ...

;

HES6 Transcription cofactor HES-6 is a protein that in humans is encoded by the ''HES6'' gene. Interactions HES6 has been shown to interact with TLE1 Transducin-like enhancer protein 1 is a protein that in humans is encoded by the ''TLE1'' gene. ...

; HES7;

;

HIF1A Hypoxia-inducible factor 1-alpha, also known as HIF-1-alpha, is a subunit of a heterodimeric transcription factor hypoxia-inducible factor 1 (HIF-1) that is encoded by the ''HIF1A'' gene. The Nobel Prize in Physiology or Medicine 2019 was awarded ...

;

ID1 DNA-binding protein inhibitor ID-1 is a protein that in humans is encoded by the ''ID1'' gene. Function The protein encoded by this gene is a helix-loop-helix (HLH) protein that can form heterodimers with members of the basic HLH family of ...

;

ID2 DNA-binding protein inhibitor ID-2 is a protein that in humans is encoded by the ''ID2'' gene. Function The protein encoded by this gene belongs to the inhibitor of DNA binding (ID) family, members of which are transcriptional regulators that ...

;

ID3 ID3 is a metadata container most often used in conjunction with the MP3 audio file format. It allows information such as the title, artist, album, track number, and other information about the file to be stored in the file itself. There are two ...

;

ID4 ID4 is a protein coding gene. In humans, it encodes for the protein known as DNA-binding protein inhibitor ID-4. This protein is known to be involved in the regulation of many cellular processes during both prenatal development and tumorigenesi ...

; KIAA2018;

LYL1 Protein lyl-1 is a protein that in humans is encoded by the ''LYL1'' gene. Interactions LYL1 has been shown to interact with TCF3 and NFKB1 Nuclear factor NF-kappa-B p105 subunit is a protein that in humans is encoded by the ''NFKB1'' gene. ...

; MASH1; MATH2; MAX;

MESP1 Mesoderm posterior 1 homolog (mouse) is a protein that in humans is encoded by the MESP1 gene In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''genera ...

;

MESP2 Mesoderm posterior protein 2 (MESP2), also known as class C basic helix-loop-helix protein 6 (bHLHc6), is a protein that in humans is encoded by the ''MESP2'' gene. Function This gene encodes a member of the bHLH family of transcription facto ...

; MIST1;

MITF Microphthalmia-associated transcription factor also known as class E basic helix-loop-helix protein 32 or bHLHe32 is a protein that in humans is encoded by the ''MITF'' gene. MITF is a basic helix-loop-helix leucine zipper transcription factor ...

; MLX; MLXIP;

MLXIPL Carbohydrate-responsive element-binding protein (ChREBP) also known as MLX-interacting protein-like (MLXIPL) is a protein that in humans is encoded by the ''MLXIPL'' gene. The protein name derives from the protein's interaction with carbohydrate r ...

; MNT;

MSC MSC may refer to: Computers * Message Sequence Chart * Microelectronics Support Centre of UK Rutherford Appleton Laboratory * MIDI Show Control * MSC Malaysia (formerly known as Multimedia Super Corridor) * USB mass storage device class (USB MSC ...

; MSGN1;

MXD1 MAD protein is a protein that in humans is encoded by the ''MXD1'' gene. MAD-MAX dimerization protein belongs to a subfamily of MAX-interacting proteins. This protein competes with MYC for binding to MAX to form a sequence-specific DNA-binding c ...

;

MXD3 MAX dimerization protein 3 is a protein that in humans is encoded by the ''MXD3'' gene located on Chromosome 5. MXD3 is a basic helix-loop-helix protein belonging to a subfamily of MAX-interacting proteins. This protein competes with MYC for bin ...

; MXD4;

MXI1 MAX-interacting protein 1 is a protein that in humans is encoded by the ''MXI1'' gene. Function Expression of the c-myc gene, which produces an oncogenic transcription factor, is tightly regulated in normal cells but is frequently deregulated ...

;

MYC ''Myc'' is a family of regulator genes and proto-oncogenes that code for transcription factors. The ''Myc'' family consists of three related human genes: ''c-myc'' (MYC), ''l-myc'' (MYCL), and ''n-myc'' (MYCN). ''c-myc'' (also sometimes referre ...

;

MYCL1 L-myc-1 proto-oncogene protein is a protein that in humans is encoded by the ''MYCL1'' gene. MYCL1 is a bHLH (basic helix-loop-helix) transcription factor implicated in lung cancer. Interactions MYCL1 has been shown to interact Advocate ...

; MYCL2;

MYCN N-myc proto-oncogene protein also known as N-Myc or basic helix-loop-helix protein 37 (bHLHe37), is a protein that in humans is encoded by the ''MYCN'' gene. Function The ''MYCN'' gene is a member of the MYC family of transcription factors an ...

; MYF5; MYF6;

MYOD1 MyoD, also known as myoblast determination protein 1, is a protein in animals that plays a major role in regulating muscle differentiation. MyoD, which was discovered in the laboratory of Harold M. Weintraub, belongs to a family of proteins kno ...

; MYOG;

NCOA1 The nuclear receptor coactivator 1 (''NCOA1'') is a transcriptional coregulatory protein that contains several nuclear receptor interacting domains and an intrinsic histone acetyltransferase activity. NCOA1 is recruited to DNA promotion sites by ...

;

NCOA3 The nuclear receptor coactivator 3 also known as NCOA3 is a protein that, in humans, is encoded by the ''NCOA3'' gene. NCOA3 is also frequently called 'amplified in breast 1' (AIB1), steroid receptor coactivator-3 (SRC-3), or thyroid hormone recept ...

;

NEUROD1 Neurogenic differentiation 1 (Neurod1), also called β2, is a transcription factor of the NeuroD-type. It is encoded by the human gene NEUROD1. In mice, ''Neurod1'' expression is first seen at embryonic day 12 (E12). It is a member of the Neurod ...

; NEUROD2; NEUROD4; NEUROD6;

NEUROG1 Neurogenin-1 is a protein that in humans is encoded by the ''NEUROG1'' gene. Interactions NEUROG1 has been shown to interact with CREB-binding protein and decapentaplegic homolog 1 Decapentaplegic (Dpp) is a key morphogen involved in the de ...

;

NEUROG2 Neurogenin-2 is a protein that in humans is encoded by the ''NEUROG2'' gene. Neurogenin-2 is a member of the neurogenin subfamily of basic helix-loop-helix ( bHLH) transcription factor genes that play an important role in neurogenesis Neurogene ...

;

NEUROG3 Neurogenin-3 (NGN3) is a protein that in humans is encoded by the Neurog3 gene. Neurogenin-3 is a pro-endocrine transcription factor that is a member of the basic helix-loop-helix (bHLH) transcription factor and has a primary function of activat ...

; NHLH1; NHLH2;

;

NPAS2 Neuronal PAS domain protein 2 (NPAS2) also known as member of PAS protein 4 (MOP4) is a transcription factor protein that in humans is encoded by the ''NPAS2'' gene. NPAS2 is paralogous to CLOCK, and both are key proteins involved in the maintenan ...

;

; NPAS4; OAF1;

OLIG1 Oligodendrocyte transcription factor 1 is a protein that in humans is encoded by the ''OLIG1'' gene. See also * Oligodendrocyte * Transcription factor * OLIG2 Oligodendrocyte transcription factor (OLIG2) is a basic helix-loop-helix ( bHLH) tr ...

;

OLIG2 Oligodendrocyte transcription factor (OLIG2) is a basic helix-loop-helix ( bHLH) transcription factor encoded by the ''Olig2'' gene. The protein is of 329 amino acids in length, 32 kDa in size and contains one basic helix-loop-helix DNA-binding do ...

; OLIG3;

PTF1A Pancreas transcription factor 1 subunit alpha is a protein that in humans is encoded by the ''PTF1A'' gene. Function This gene encodes a protein that is a component of the pancreas transcription factor 1 complex (PTF1) and is known to have a r ...

; SCL; SCXB;

SIM1 Single-minded homolog 1, also known as class E basic helix-loop-helix protein 14 (bHLHe14), is a protein that in humans is encoded by the ''SIM1'' gene. Function SIM1 and SIM2 genes are homologs of ''Drosophila melanogaster'' single-minded (sim), ...

;

SIM2 Single-minded homolog 2 is a protein that in humans is encoded by the ''SIM2'' gene. It plays a major role in the development of the central nervous system midline as well as the construction of the face and head. Function SIM1 and SIM2 genes ...

; SOHLH1; SOHLH2;

SREBF1 Sterol regulatory element-binding transcription factor 1 (SREBF1) also known as sterol regulatory element-binding protein 1 (SREBP-1) is a protein that in humans is encoded by the ''SREBF1'' gene. This gene is located within the Smith–Magenis s ...

;

SREBF2 Sterol regulatory element-binding protein 2 (SREBP-2) also known as sterol regulatory element binding transcription factor 2 (SREBF2) is a protein that in humans is encoded by the ''SREBF2'' gene. Function This gene encodes a ubiquitously expr ...

;

TAL1 __NOTOC__ T-cell acute lymphocytic leukemia protein 1 (i.e. TAL1 but also termed stem cell leukemia/T-cell acute leukemia 1 .e. SCL/TAL1 is a protein that in humans is encoded by the ''TAL1'' gene. The protein encoded by TAL1 is a basic helix-lo ...

; TAL2;

TCF12 Transcription factor 12 is a protein that in humans is encoded by the ''TCF12'' gene. The protein encoded by this gene is a member of the basic helix-loop-helix (bHLH) E-protein family that recognizes the consensus binding site (E-box) CANNTG. Th ...

; TCF15;

TCF21 Transcription factor 21 (TCF21), also known as pod-1, capsuling, or epicardin, is a protein that in humans is encoded by the ''TCF21'' gene on chromosome 6. It is ubiquitously expressed in many tissues and cell types and highly significantly expr ...

;

TCF3 Transcription factor 3 (E2A immunoglobulin enhancer-binding factors E12/E47), also known as TCF3, is a protein that in humans is encoded by the ''TCF3'' gene. TCF3 has been shown to directly enhance Hes1 (a well-known target of Notch signaling) ex ...

;

; TCFL5;

TFAP4 Transcription factor AP-4 (activating enhancer binding protein 4), also known as TFAP4, is a protein which in humans is encoded by the TFAP4 gene. Function Transcription factor AP4 is a member of the basic helix-loop-helix (bHLH) transcriptio ...

;

TFE3 Transcription factor E3 is a protein that in humans is encoded by the ''TFE3'' gene. Function TFE3, a member of the helix-loop-helix family of transcription factors, binds to the mu-E3 motif of the immunoglobulin heavy-chain enhancer and is ex ...

;

TFEB Transcription factor EB is a protein that in humans is encoded by the ''TFEB'' gene. Function TFEB is a master gene for lysosomal biogenesis. It encodes a transcription factor that coordinates expression of lysosomal hydrolases, membrane protei ...

; TFEC;

TWIST1 Twist-related protein 1 (TWIST1) also known as class A basic helix–loop–helix protein 38 (bHLHa38) is a basic helix-loop-helix transcription factor that in humans is encoded by the ''TWIST1'' gene. Function Basic helix-loop-helix (bHLH) tr ...

;

TWIST2 Twist-related protein 2 is a protein that in humans is encoded by the ''TWIST2'' gene. The protein encoded by this gene is a basic helix-loop-helix (bHLH) transcription factor and shares similarity with another bHLH transcription factor, TWIST1. ...

;

USF1 Upstream stimulatory factor 1 is a protein that in humans is encoded by the ''USF1'' gene. Function This gene encodes a member of the basic helix-loop-helix leucine zipper family and can function as a cellular transcription factor. The encode ...

;

USF2 Upstream stimulatory factor 2 is a protein that in humans is encoded by the ''USF2'' gene. Function This gene encodes a member of the basic helix-loop-helix leucine zipper family, and can function as a cellular transcription factor. The encode ...

;

References

External links

PDOC00038
in

PROSITE PROSITE is a protein database. It consists of entries describing the protein families, domains and functional sites as well as amino acid patterns and profiles in them. These are manually curated by a team of the Swiss Institute of Bioinformati ...

*
bHLH family
a
PlantTFDB:Plant Transcription Factor Database
{{DEFAULTSORT:Basic helix-loop-helix Protein domains Protein structural motifs DNA-binding substances