Covalent attachment of small ubiquitin-like modifier (SUMO) to proteins regulates many processes in the eukaryotic cell. This reaction is similar to ubiquitination and usually requires an E3 ligase for substrate modification. However, only a few SUMO ligases have been described so far, which frequently facilitate sumoylation by bringing together the SUMO-conjugating enzyme Ubc9 and the target protein. Ubc9 is an interaction partner of the transcription factor Krox20, a key regulator of hindbrain development. Here, we show that Krox20 functions as a SUMO ligase for its coregulators--the Nab proteins--and that Nab sumoylation negatively modulates Krox20 transcriptional activity in vivo.
E3 SUMO-protein ligase helping SUMO1 conjugation to its coregulators NAB1 and NAB2, whose sumoylation down-regulates EGR2 own transcriptional activity.
Covalent attachment of small ubiquitin-like modifier (SUMO) to proteins regulates many processes in the eukaryotic cell. This reaction is similar to ubiquitination and usually requires an E3 ligase for substrate modification. However, only a few SUMO ligases have been described so far, which frequently facilitate sumoylation by bringing together the SUMO-conjugating enzyme Ubc9 and the target protein. Ubc9 is an interaction partner of the transcription factor Krox20, a key regulator of hindbrain development. Here, we show that Krox20 functions as a SUMO ligase for its coregulators--the Nab proteins--and that Nab sumoylation negatively modulates Krox20 transcriptional activity in vivo.
Interacting selectively and non-covalently with chromatin, the network of fibers of DNA, protein, and sometimes RNA, that make up the chromosomes of the eukaryotic nucleus during interphase.
Interacting selectively and non-covalently with an HMG box domain, a protein domain that consists of three helices in an irregular array. HMG-box domains are found in one or more copies in HMG-box proteins, which form a large, diverse family involved in the regulation of DNA-dependent processes such as transcription, replication, and strand repair, all of which require the bending and unwinding of chromatin.
Catalysis of the joining of two substances, or two groups within a single molecule, with the concomitant hydrolysis of the diphosphate bond in ATP or a similar triphosphate.
Interacting selectively and non-covalently with any protein or protein complex (a complex of two or more proteins that may include other nonprotein molecules).
Evidence
1:
Inferred from Physical InteractionUniProtKB
HCF-1 is a transcriptional cofactor required for activation of herpes simplex virus immediate-early genes by VP16 as well as less clearly defined roles in cell proliferation, cytokinesis, and spliceosome formation. It is expressed as a large precursor that undergoes proteolysis to yield two subunits that remain stably associated. VP16 uses a degenerate 4-amino acid sequence, known as the HCF-binding motif, to bind to a six-bladed beta-propeller domain at the N terminus of HCF-1. Functional HCF-binding motifs are also found in LZIP and Zhangfei, two cellular bZIP transcription factors of unknown function. Here we show that the HCF-binding motif occurs in a wide spectrum of DNA-binding proteins and transcriptional cofactors. Three well characterized examples were further analyzed for their ability to use HCF-1 as a coactivator. Krox20, a zinc finger transcription factor required for Schwann cell differentiation, and E2F4, a cell cycle regulator, showed a strong requirement for functional HCF-1 to activate transcription. In contrast, activation by estrogen receptor-alpha did not display HCF dependence. In Krox20, the HCF-binding motif lies within the N-terminal activation domain and mutation of this sequence diminishes both transactivation and association with the HCF-1 beta-propeller. The activation domain in the C-terminal subunit of HCF-1 contributes to activation by Krox20, possibly through recruitment of p300. These results suggest that HCF-1 is recruited by many different classes of cellular transcription factors and is therefore likely to be required for a variety of cellular processes including cell cycle progression and development.
Interacting selectively and non-covalently with an RNA polymerase II transcription activating factor, a protein involved in positive regulation of transcription.
Interacting selectively and non-covalently with a specific DNA sequence in order to modulate transcription. The transcription factor may or may not also interact selectively with a protein or macromolecular complex.
HCF-1 is a transcriptional cofactor required for activation of herpes simplex virus immediate-early genes by VP16 as well as less clearly defined roles in cell proliferation, cytokinesis, and spliceosome formation. It is expressed as a large precursor that undergoes proteolysis to yield two subunits that remain stably associated. VP16 uses a degenerate 4-amino acid sequence, known as the HCF-binding motif, to bind to a six-bladed beta-propeller domain at the N terminus of HCF-1. Functional HCF-binding motifs are also found in LZIP and Zhangfei, two cellular bZIP transcription factors of unknown function. Here we show that the HCF-binding motif occurs in a wide spectrum of DNA-binding proteins and transcriptional cofactors. Three well characterized examples were further analyzed for their ability to use HCF-1 as a coactivator. Krox20, a zinc finger transcription factor required for Schwann cell differentiation, and E2F4, a cell cycle regulator, showed a strong requirement for functional HCF-1 to activate transcription. In contrast, activation by estrogen receptor-alpha did not display HCF dependence. In Krox20, the HCF-binding motif lies within the N-terminal activation domain and mutation of this sequence diminishes both transactivation and association with the HCF-1 beta-propeller. The activation domain in the C-terminal subunit of HCF-1 contributes to activation by Krox20, possibly through recruitment of p300. These results suggest that HCF-1 is recruited by many different classes of cellular transcription factors and is therefore likely to be required for a variety of cellular processes including cell cycle progression and development.
Interacting selectively and non-covalently with a DNA region that regulates the transcription of a region of DNA, which may be a gene, cistron, or operon. Binding may occur as a sequence specific interaction or as an interaction observed only once a factor has been recruited to the DNA by other factors.
E3 ubiquitin ligases, which target specific molecules for proteolytic destruction, have emerged as key regulators of immune functions. Several E3 ubiquitin ligases, including c-Cbl, Cbl-b, GRAIL, Itch, and Nedd4, have been shown to negatively regulate T-cell activation. Here, we report that the HECT-type E3 ligase AIP2 positively regulates T-cell activation. Ectopic expression of AIP2 in mouse primary T cells enhances their proliferation and interleukin-2 production by suppressing the apoptosis of T cells. AIP2 interacts with and promotes ubiquitin-mediated degradation of EGR2, a zinc finger transcription factor that has been found to regulate Fas ligand (FasL) expression during activation-induced T-cell death. Suppression of AIP2 expression by small RNA interference upregulates EGR2, inhibits EGR2 ubiquitination and FasL expression, and enhances the apoptosis of T cells. Therefore, AIP2 regulates activation-induced T-cell death by suppressing EGR2-mediated FasL expression via the ubiquitin pathway.
The process whose specific outcome is the progression of the brain over time, from its formation to the mature structure. Brain development begins with patterning events in the neural tube and ends with the mature structure that is the center of thought and emotion. The brain is responsible for the coordination and control of bodily activities and the interpretation of information from the senses (sight, hearing, smell, etc.).
The early growth response 2 gene (EGR2) is part of a multigene family encoding Cys2His2 type zinc-finger proteins and may play a role in the regulation of cellular proliferation. Egr2, (also known as Krox20) is the mouse orthologue of human EGR2 and was first identified as an immediate-early response gene, encoding a protein that binds DNA in a sequence-specific manner and acts as a transcription factor. Stable expression of Egr2 is specifically associated with the onset of myelination in the peripheral nervous system (PNS). Egr2(-/-) mice display disrupted hindbrain segmentation and development, and a block of Schwann-cell differentiation at an early stage. We hypothesized that Egr2 may be a transcription factor affecting late myelin genes and that human myelinopathies of the PNS may result from mutations in EGR2. In support of this hypothesis, we have identified one recessive and two dominant missense mutations in EGR2 (within regions encoding conserved functional domains) in patients with congenital hypomyelinating neuropathy (CHN) and a family with Charcot-Marie-Tooth type 1 (CMT1).
Any process that results in a change in state or activity of a cell (in terms of movement, secretion, enzyme production, gene expression, etc.) as a result of an organic substance stimulus.
The process that contributes to the act of creating the structural organization of the facial nerve. This process pertains to the physical shaping of a rudimentary structure. This sensory and motor nerve supplies the muscles of facial expression and the expression and taste at the anterior two-thirds of the tongue. The principal branches are the superficial opthalmic, buccal, palatine and hyomandibular. The main trunk synapses within pterygopalatine ganglion in the parotid gland and this ganglion then gives of nerve branches which supply the lacrimal gland and the mucous secreting glands of the nasal and oral cavities.
The process in which a relatively unspecialized cell acquires specialized features of an adipocyte, an animal connective tissue cell specialized for the synthesis and storage of fat.
The process in which the migration of an axon growth cone of a motor neuron is directed to a specific target site in response to a combination of attractive and repulsive cues.
The process in which myelin sheaths are formed and maintained around neurons. Oligodendrocytes in the brain and spinal cord and Schwann cells in the peripheral nervous system wrap axons with compact layers of their plasma membrane. Adjacent myelin segments are separated by a non-myelinated stretch of axon called a node of Ranvier.
The process whose specific outcome is the progression of the peripheral nervous system over time, from its formation to the mature structure. The peripheral nervous system is one of the two major divisions of the nervous system. Nerves in the PNS connect the central nervous system (CNS) with sensory organs, other organs, muscles, blood vessels and glands.
The early growth response 2 gene (EGR2) is part of a multigene family encoding Cys2His2 type zinc-finger proteins and may play a role in the regulation of cellular proliferation. Egr2, (also known as Krox20) is the mouse orthologue of human EGR2 and was first identified as an immediate-early response gene, encoding a protein that binds DNA in a sequence-specific manner and acts as a transcription factor. Stable expression of Egr2 is specifically associated with the onset of myelination in the peripheral nervous system (PNS). Egr2(-/-) mice display disrupted hindbrain segmentation and development, and a block of Schwann-cell differentiation at an early stage. We hypothesized that Egr2 may be a transcription factor affecting late myelin genes and that human myelinopathies of the PNS may result from mutations in EGR2. In support of this hypothesis, we have identified one recessive and two dominant missense mutations in EGR2 (within regions encoding conserved functional domains) in patients with congenital hypomyelinating neuropathy (CHN) and a family with Charcot-Marie-Tooth type 1 (CMT1).
The process in which a SUMO protein (small ubiquitin-related modifier) is conjugated to a target protein via an isopeptide bond between the carboxyl terminus of SUMO with an epsilon-amino group of a lysine residue of the target protein.
A process that modulates neuronal synaptic plasticity, the ability of neuronal synapses to change as circumstances require. They may alter function, such as increasing or decreasing their sensitivity, or they may increase or decrease in actual numbers.
Any process that results in a change in state or activity of a cell or an organism (in terms of movement, secretion, enzyme production, gene expression, etc.) as a result of an insulin stimulus. Insulin is a polypeptide hormone produced by the islets of Langerhans of the pancreas in mammals, and by the homologous organs of other organisms.
The process that gives rise to rhombomere 3. This process pertains to the initial formation of a structure from unspecified parts. Rhombomeres are transverse segments of the developing rhombencephalon. Rhombomeres are lineage restricted, express different genes from one another, and adopt different developmental fates. Rhombomeres are numbered in anterior to posterior order.
The process that gives rise to rhombomere 5. This process pertains to the initial formation of a structure from unspecified parts. Rhombomeres are transverse segments of the developing rhombencephalon. Rhombomeres are lineage restricted, express different genes from one another, and adopt different developmental fates. Rhombomeres are numbered in anterior to posterior order.
The process in which a relatively unspecialized cell acquires the specialized features of a Schwann cell. Schwann cells are found in the peripheral nervous system, where they insulate neurons and axons, and regulate the environment in which neurons function.
The synthesis of RNA from a DNA template by RNA polymerase II, originating at an RNA polymerase II promoter. Includes transcription of messenger RNA (mRNA) and certain small nuclear RNAs (snRNAs).
Protein involved in the transfer of genetic information from DNA to messenger RNA (mRNA) by DNA-directed RNA polymerase. In the case of some RNA viruses, protein involved in the transfer of genetic information from RNA to messenger RNA (mRNA) by RNA-directed RNA polymerase.
Protein involved in ubiquitin-like modifier processing, activation, conjugation or deconjugation such as Ubl-activating enzymes (E1s), Ubl-conjugating enzymes (E2s), Ubl-protein ligases (E3s), some thiol proteases (Ubiquitin carboxyl-terminal hydrolases (UCH), Ubiquitin- specific processing proteases (UBP) and ubiquitin-like proteases) and the ubiquitin-like modifier proteins. Besides signaling proteolysis, ubiquitination for example can be a signal for trafficking, kinase activation and other nonproteolytic fates.
Enzyme that catalyzes the joining of two molecules coupled with the breakdown of a pyrophosphate bond in ATP or a similar triphosphate. Sometimes the terms "synthase", "synthetase" or "carboxylase" are also used for this class of enzymes.
A reference proteome is a set of protein sequences derived from a complete proteome which constitutes a defined standard for a particular user community. Reference proteomes are manually defined according to a number of criteria. They cover the proteomes of well- studied model organisms and other proteomes of interest for biomedical and biotechnological research. Reference proteomes have been selected to provide broad coverage of the tree of life, and constitute a representative cross-section of the taxonomic diversity to be found within UniProtKB.