Histone acetyltransferase p300 also known as p300 HAT or E1A-associated protein p300 (where E1A =
adenovirus early region 1A) also known as EP300 or p300 is an
enzyme that, in humans, is encoded by the EP300gene.[5] It functions as
histone acetyltransferase that regulates transcription of genes via
chromatin remodeling by allowing
histone proteins to wrap DNA less tightly. This enzyme plays an essential role in regulating
cell growth and
division, prompting cells to mature and assume specialized functions (differentiate), and preventing the growth of cancerous tumors. The p300 protein appears to be critical for normal development before and after
birth.
The EP300 gene is located on the long (q) arm of the human
chromosome 22 at position 13.2. This gene encodes the
adenovirusE1A-associated cellular p300 transcriptional co-activator protein.
p300 HAT functions as
histone acetyltransferase[6] that regulates transcription via chromatin remodeling, and is important in the processes of cell proliferation and differentiation. It mediates
cAMP-gene regulation by binding specifically to phosphorylated
CREB protein.
p300 HAT contains a
bromodomain which is involved in IL6 signaling.[7]: 3.1
This gene has also been identified as a co-activator of
HIF1A (hypoxia-inducible factor 1 alpha), and, thus, plays a role in the stimulation of hypoxia-induced genes such as
VEGF.[8]
Mechanism
The p300 protein carries out its function of activating
transcription by binding to
transcription factors, and the transcription machinery. On the basis of this function, p300 is called a transcriptional
coactivator. The p300 interaction with transcription factors is managed by one or more of p300 domains: the
nuclear receptor interaction domain (RID), the
KIX domain (
CREB and
MYB interaction domain), the
cysteine/
histidine regions (TAZ1/CH1 and TAZ2/CH3) and the
interferon response binding domain (IBiD). The last four domains, KIX, TAZ1, TAZ2 and IBiD of p300, each bind tightly to a sequence spanning both
transactivation domains 9aaTADs of transcription factor p53.[9]
Clinical significance
Mutations in the EP300 gene are responsible for a small percentage of cases of
Rubinstein-Taybi syndrome. These mutations result in the loss of one copy of the gene in each cell, which reduces the amount of p300 protein by half. Some mutations lead to the production of a very short, nonfunctional version of the p300 protein, while others prevent one copy of the gene from making any protein at all. Although researchers do not know how a reduction in the amount of p300 protein leads to the specific features of Rubinstein-Taybi syndrome, it is clear that the loss of one copy of the EP300 gene disrupts normal development.[citation needed]
Chromosomal rearrangements involving chromosome 22 have rarely been associated with certain types of
cancer. These rearrangements, called
translocations, disrupt the region of chromosome 22 that contains the EP300 gene. For example, researchers have found a translocation between chromosomes 8 and 22 in several people with a cancer of blood cells called
acute myeloid leukemia (AML). Another translocation, involving chromosomes 11 and 22, has been found in a small number of people who have undergone cancer treatment. This chromosomal change is associated with the development of AML following chemotherapy for other forms of cancer.[citation needed]
Mutations in the EP300 gene have been identified in several other types of cancer. These mutations are somatic, which means they are acquired during a person's lifetime and are present only in certain cells. Somatic mutations in the EP300 gene have been found in a small number of solid tumors, including cancers of the
colon and
rectum,
stomach,
breast, and
pancreas. Studies suggest that EP300 mutations may also play a role in the development of some
prostate cancers, and could help predict whether these tumors will increase in size or spread to other parts of the body. In cancer cells, EP300 mutations prevent the gene from producing any functional protein. Without p300, cells cannot effectively restrain growth and division, which can allow cancerous tumors to form.[citation needed]
^
abFan S, Ma YX, Wang C, Yuan RQ, Meng Q, Wang JA, Erdos M, Goldberg ID, Webb P, Kushner PJ, Pestell RG, Rosen EM (January 2002). "p300 Modulates the BRCA1 inhibition of estrogen receptor activity". Cancer Res. 62 (1): 141–51.
PMID11782371.
^
abShiseki M, Nagashima M, Pedeux RM, Kitahama-Shiseki M, Miura K, Okamura S, Onogi H, Higashimoto Y, Appella E, Yokota J, Harris CC (May 2003). "p29ING4 and p28ING5 bind to p53 and p300, and enhance p53 activity". Cancer Res. 63 (10): 2373–8.
PMID12750254.
^Pearson KL, Hunter T, Janknecht R (December 1999). "Activation of Smad1-mediated transcription by p300/CBP". Biochim. Biophys. Acta. 1489 (2–3): 354–64.
doi:
10.1016/S0167-4781(99)00166-9.
PMID10673036.
^
abNakashima K, Yanagisawa M, Arakawa H, Kimura N, Hisatsune T, Kawabata M, Miyazono K, Taga T (April 1999). "Synergistic signaling in fetal brain by STAT3-Smad1 complex bridged by p300". Science. 284 (5413): 479–82.
Bibcode:
1999Sci...284..479N.
doi:
10.1126/science.284.5413.479.
PMID10205054.
Ott M, Dorr A, Hetzer-Egger C, Kaehlcke K, Schnolzer M, Henklein P, Cole P, Zhou MM, Verdin E (2004). "Tat acetylation: a regulatory switch between early and late phases in HIV transcription elongation". Reversible Protein Acetylation. Novartis Foundation Symposia. Vol. 259. pp. 182–93, discussion 193–6, 223–5.
doi:
10.1002/0470862637.ch13.
ISBN978-0-470-86263-6.
PMID15171254.
1f81: SOLUTION STRUCTURE OF THE TAZ2 DOMAIN OF THE TRANSCRIPTIONAL ADAPTOR PROTEIN CBP
1jsp: NMR Structure of CBP Bromodomain in complex with p53 peptide
1kdx: KIX DOMAIN OF MOUSE CBP (CREB BINDING PROTEIN) IN COMPLEX WITH PHOSPHORYLATED KINASE INDUCIBLE DOMAIN (PKID) OF RAT CREB (CYCLIC AMP RESPONSE ELEMENT BINDING PROTEIN), NMR 17 STRUCTURES
1l3e: NMR Structures of the HIF-1alpha CTAD/p300 CH1 Complex
1l8c: STRUCTURAL BASIS FOR HIF-1ALPHA/CBP RECOGNITION IN THE CELLULAR HYPOXIC RESPONSE
1p4q: Solution structure of the CITED2 transactivation domain in complex with the p300 CH1 domain
1r8u: NMR structure of CBP TAZ1/CITED2 complex
1u2n: Structure CBP TAZ1 Domain
2d82: Target Structure-Based Discovery of Small Molecules that Block Human p53 and CREB Binding Protein (CBP) Association
Histone acetyltransferase p300 also known as p300 HAT or E1A-associated protein p300 (where E1A =
adenovirus early region 1A) also known as EP300 or p300 is an
enzyme that, in humans, is encoded by the EP300gene.[5] It functions as
histone acetyltransferase that regulates transcription of genes via
chromatin remodeling by allowing
histone proteins to wrap DNA less tightly. This enzyme plays an essential role in regulating
cell growth and
division, prompting cells to mature and assume specialized functions (differentiate), and preventing the growth of cancerous tumors. The p300 protein appears to be critical for normal development before and after
birth.
The EP300 gene is located on the long (q) arm of the human
chromosome 22 at position 13.2. This gene encodes the
adenovirusE1A-associated cellular p300 transcriptional co-activator protein.
p300 HAT functions as
histone acetyltransferase[6] that regulates transcription via chromatin remodeling, and is important in the processes of cell proliferation and differentiation. It mediates
cAMP-gene regulation by binding specifically to phosphorylated
CREB protein.
p300 HAT contains a
bromodomain which is involved in IL6 signaling.[7]: 3.1
This gene has also been identified as a co-activator of
HIF1A (hypoxia-inducible factor 1 alpha), and, thus, plays a role in the stimulation of hypoxia-induced genes such as
VEGF.[8]
Mechanism
The p300 protein carries out its function of activating
transcription by binding to
transcription factors, and the transcription machinery. On the basis of this function, p300 is called a transcriptional
coactivator. The p300 interaction with transcription factors is managed by one or more of p300 domains: the
nuclear receptor interaction domain (RID), the
KIX domain (
CREB and
MYB interaction domain), the
cysteine/
histidine regions (TAZ1/CH1 and TAZ2/CH3) and the
interferon response binding domain (IBiD). The last four domains, KIX, TAZ1, TAZ2 and IBiD of p300, each bind tightly to a sequence spanning both
transactivation domains 9aaTADs of transcription factor p53.[9]
Clinical significance
Mutations in the EP300 gene are responsible for a small percentage of cases of
Rubinstein-Taybi syndrome. These mutations result in the loss of one copy of the gene in each cell, which reduces the amount of p300 protein by half. Some mutations lead to the production of a very short, nonfunctional version of the p300 protein, while others prevent one copy of the gene from making any protein at all. Although researchers do not know how a reduction in the amount of p300 protein leads to the specific features of Rubinstein-Taybi syndrome, it is clear that the loss of one copy of the EP300 gene disrupts normal development.[citation needed]
Chromosomal rearrangements involving chromosome 22 have rarely been associated with certain types of
cancer. These rearrangements, called
translocations, disrupt the region of chromosome 22 that contains the EP300 gene. For example, researchers have found a translocation between chromosomes 8 and 22 in several people with a cancer of blood cells called
acute myeloid leukemia (AML). Another translocation, involving chromosomes 11 and 22, has been found in a small number of people who have undergone cancer treatment. This chromosomal change is associated with the development of AML following chemotherapy for other forms of cancer.[citation needed]
Mutations in the EP300 gene have been identified in several other types of cancer. These mutations are somatic, which means they are acquired during a person's lifetime and are present only in certain cells. Somatic mutations in the EP300 gene have been found in a small number of solid tumors, including cancers of the
colon and
rectum,
stomach,
breast, and
pancreas. Studies suggest that EP300 mutations may also play a role in the development of some
prostate cancers, and could help predict whether these tumors will increase in size or spread to other parts of the body. In cancer cells, EP300 mutations prevent the gene from producing any functional protein. Without p300, cells cannot effectively restrain growth and division, which can allow cancerous tumors to form.[citation needed]
^
abFan S, Ma YX, Wang C, Yuan RQ, Meng Q, Wang JA, Erdos M, Goldberg ID, Webb P, Kushner PJ, Pestell RG, Rosen EM (January 2002). "p300 Modulates the BRCA1 inhibition of estrogen receptor activity". Cancer Res. 62 (1): 141–51.
PMID11782371.
^
abShiseki M, Nagashima M, Pedeux RM, Kitahama-Shiseki M, Miura K, Okamura S, Onogi H, Higashimoto Y, Appella E, Yokota J, Harris CC (May 2003). "p29ING4 and p28ING5 bind to p53 and p300, and enhance p53 activity". Cancer Res. 63 (10): 2373–8.
PMID12750254.
^Pearson KL, Hunter T, Janknecht R (December 1999). "Activation of Smad1-mediated transcription by p300/CBP". Biochim. Biophys. Acta. 1489 (2–3): 354–64.
doi:
10.1016/S0167-4781(99)00166-9.
PMID10673036.
^
abNakashima K, Yanagisawa M, Arakawa H, Kimura N, Hisatsune T, Kawabata M, Miyazono K, Taga T (April 1999). "Synergistic signaling in fetal brain by STAT3-Smad1 complex bridged by p300". Science. 284 (5413): 479–82.
Bibcode:
1999Sci...284..479N.
doi:
10.1126/science.284.5413.479.
PMID10205054.
Ott M, Dorr A, Hetzer-Egger C, Kaehlcke K, Schnolzer M, Henklein P, Cole P, Zhou MM, Verdin E (2004). "Tat acetylation: a regulatory switch between early and late phases in HIV transcription elongation". Reversible Protein Acetylation. Novartis Foundation Symposia. Vol. 259. pp. 182–93, discussion 193–6, 223–5.
doi:
10.1002/0470862637.ch13.
ISBN978-0-470-86263-6.
PMID15171254.
1f81: SOLUTION STRUCTURE OF THE TAZ2 DOMAIN OF THE TRANSCRIPTIONAL ADAPTOR PROTEIN CBP
1jsp: NMR Structure of CBP Bromodomain in complex with p53 peptide
1kdx: KIX DOMAIN OF MOUSE CBP (CREB BINDING PROTEIN) IN COMPLEX WITH PHOSPHORYLATED KINASE INDUCIBLE DOMAIN (PKID) OF RAT CREB (CYCLIC AMP RESPONSE ELEMENT BINDING PROTEIN), NMR 17 STRUCTURES
1l3e: NMR Structures of the HIF-1alpha CTAD/p300 CH1 Complex
1l8c: STRUCTURAL BASIS FOR HIF-1ALPHA/CBP RECOGNITION IN THE CELLULAR HYPOXIC RESPONSE
1p4q: Solution structure of the CITED2 transactivation domain in complex with the p300 CH1 domain
1r8u: NMR structure of CBP TAZ1/CITED2 complex
1u2n: Structure CBP TAZ1 Domain
2d82: Target Structure-Based Discovery of Small Molecules that Block Human p53 and CREB Binding Protein (CBP) Association