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Cyclin-dependent Kinase Complex
A cyclin-dependent kinase complex (CDKC, cyclin-CDK) is a protein complex formed by the association of an inactive catalytic subunit of a protein kinase, cyclin-dependent kinase (CDK), with a regulatory subunit, cyclin.Malumbres M, Barbacid M. Mammalian cyclin-dependent kinases. Trends Biochem. Sci. 2005 Nov;30(11):630-41 Once cyclin-dependent kinases bind to cyclin, the formed complex is in an activated state. Substrate specificity of the activated complex is mainly established by the associated cyclin within the complex. Activity of CDKCs is controlled by phosphorylation of target proteins, as well as binding of inhibitory proteins.Lodish H, Baltimore D, Berk A, Zipursky SL, Matsudaira P, Darnell J. 1995. Molecular Cell Biology. 3rd Ed. New York: Scientific American Books Structure and Regulation The structure of CDKs in complex with a cyclin subunits (CDKC) has long been a goal of structural and cellular biologists starting in the 1990s when the structure of unbou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Structure Of Cdk2–cyclin A–p27
A structure is an arrangement and organization of interrelated elements in a material object or system, or the object or system so organized. Material structures include man-made objects such as buildings and machines and natural objects such as biological organisms, minerals and chemicals. Abstract structures include data structures in computer science and musical form. Types of structure include a hierarchy (a cascade of one-to-many relationships), a network featuring many-to-many links, or a lattice featuring connections between components that are neighbors in space. Load-bearing Buildings, aircraft, skeletons, anthills, beaver dams, bridges and salt domes are all examples of load-bearing structures. The results of construction are divided into buildings and non-building structures, and make up the infrastructure of a human society. Built structures are broadly divided by their varying design approaches and standards, into categories including building structures, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schizosaccharomyces Pombe
''Schizosaccharomyces pombe'', also called "fission yeast", is a species of yeast used in traditional brewing and as a model organism in molecular and cell biology. It is a unicellular eukaryote, whose cells are rod-shaped. Cells typically measure 3 to 4 micrometres in diameter and 7 to 14 micrometres in length. Its genome, which is approximately 14.1 million base pairs, is estimated to contain 4,970 protein-coding genes and at least 450 non-coding RNAs. These cells maintain their shape by growing exclusively through the cell tips and divide by medial fission to produce two daughter cells of equal size, which makes them a powerful tool in cell cycle research. Fission yeast was isolated in 1893 by Paul Lindner from East African millet beer. The species name ''pombe'' is the Swahili word for beer. It was first developed as an experimental model in the 1950s: by Urs Leupold for studying genetics, and by Murdoch Mitchison for studying the cell cycle. Paul Nurse, a fission ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meiosis
Meiosis () is a special type of cell division of germ cells in sexually-reproducing organisms that produces the gametes, the sperm or egg cells. It involves two rounds of division that ultimately result in four cells, each with only one copy of each chromosome (haploid). Additionally, prior to the division, genetic material from the paternal and maternal copies of each chromosome is crossed over, creating new combinations of code on each chromosome. Later on, during fertilisation, the haploid cells produced by meiosis from a male and a female will fuse to create a zygote, a cell with two copies of each chromosome. Errors in meiosis resulting in aneuploidy (an abnormal number of chromosomes) are the leading known cause of miscarriage and the most frequent genetic cause of developmental disabilities. In meiosis, DNA replication is followed by two rounds of cell division to produce four daughter cells, each with half the number of chromosomes as the original parent cell. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transcription (biology)
Transcription is the process of copying a segment of DNA into RNA for the purpose of gene expression. Some segments of DNA are transcribed into RNA molecules that can encode proteins, called messenger RNA (mRNA). Other segments of DNA are transcribed into RNA molecules called non-coding RNAs (ncRNAs). Both DNA and RNA are nucleic acids, which use base pairs of nucleotides as a Complementarity (molecular biology), complementary language. During transcription, a DNA sequence is read by an RNA polymerase, which produces a complementary, Antiparallel (biochemistry), antiparallel RNA strand called a primary transcript. In virology, the term transcription is used when referring to mRNA synthesis from a viral RNA molecule. The genome of many Orthornavirae, RNA viruses is composed of Sense (molecular biology), negative-sense RNA which acts as a template for positive sense viral messenger RNA - a necessary step in the synthesis of viral proteins needed for viral replication. This process ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Replication Stress
DNA replication stress refers to the state of a cell whose genome is exposed to various stresses. The events that contribute to replication stress occur during DNA replication, and can result in a stalled replication fork. There are many events that contribute to replication stress, including: * Misincorporation of ribonucleotides * Unusual DNA structures * Conflicts between replication and transcription * Insufficiency of essential replication factors * Common fragile sites * Overexpression or constitutive activation of oncogenes * Chromatin inaccessibility ATM and ATR are proteins that help to alleviate replication stress. Specifically, they are kinases that are recruited and activated by DNA damage. The stalled replication fork can collapse if these regulatory proteins fail to stabilize it. When this occurs, reassembly of the fork is initiated in order to repair the damaged DNA end. Replication fork The replication fork consists of a group of proteins that influence the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclin E/Cdk2
The Cyclin E/Cdk2 complex is a structure composed of two proteins, cyclin E and cyclin-dependent kinase 2 (Cdk2). Similar to other Cyclin-dependent kinase complex, cyclin/Cdk complexes, the cyclin E/Cdk2 Protein dimer, dimer plays a crucial role in regulating the cell cycle, with this specific complex peaking in activity during the G1/S transition. Once the cyclin and Cdk subunits join together, the complex gets activated, allowing it to Phosphorylation, phosphorylate and bind to downstream proteins to ultimately promote cell cycle progression. Although cyclin E can bind to other Cdk proteins, its primary binding partner is Cdk2, and the majority of cyclin E activity occurs when it exists as the cyclin E/Cdk2 complex. G1/S transition Across eukaryotic cell types, the cell cycle is highly conserved, and the cyclin/Cdk complexes are consistently essential in driving the entire process forwards. Shortly before the end of G1 phase, cyclin E joins with Cdk2 to activate its serine-threo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transcription Factor
In molecular biology, a transcription factor (TF) (or sequence-specific DNA-binding factor) is a protein that controls the rate of transcription (genetics), transcription of genetics, genetic information from DNA to messenger RNA, by binding to a specific DNA sequence. The function of TFs is to regulate—turn on and off—genes in order to make sure that they are Gene expression, expressed in the desired Cell (biology), cells at the right time and in the right amount throughout the life of the cell and the organism. Groups of TFs function in a coordinated fashion to direct cell division, cell growth, and cell death throughout life; cell migration and organization (body plan) during embryonic development; and intermittently in response to signals from outside the cell, such as a hormone. There are approximately 1600 TFs in the human genome. Transcription factors are members of the proteome as well as regulome. TFs work alone or with other proteins in a complex, by promoting (a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retinoblastoma Protein
Retinoblastoma (Rb) is a rare form of cancer that rapidly develops from the immature cells of a retina, the light-detecting tissue of the eye. It is the most common primary malignant intraocular cancer in children, and 80% of retinoblastoma cases are first detected in those under 3 years old. Though most children in high income countries survive this cancer, they may lose their vision in the affected eye(s) or need to have the eye removed. Almost half of children with retinoblastoma have a hereditary genetic defect associated with it. In other cases, retinoblastoma is caused by a congenital mutation in the chromosome 13 gene 13q14 ( retinoblastoma protein). Signs and symptoms Retinoblastoma is the most intrusive intraocular cancer among children. The chance of survival and preservation of the eye depends fully on the severity. Retinoblastoma is extremely rare as there are only about 200 to 300 cases every year in the United States. Globally, only 1 in about 15,000 childre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclin Expression
Cyclins are proteins that control the progression of a cell through the cell cycle by activating cyclin-dependent kinases (CDK). Etymology Cyclins were originally discovered by R. Timothy Hunt in 1982 while studying the cell cycle of sea urchins. In an interview hosted by Jim Al-Khalili and R. Timothy Hunt for "The Life Scientific", which aired on December 13, 2011, explained that the name "cyclin" was originally named after his hobby cycling. It was only after the naming did its importance in the cell cycle become apparent. As it was appropriate, the name stuck. R. Timothy Hunt: "By the way, the name cyclin, which I coined, was really a joke, it's because I liked cycling so much at the time, but they did come and go in the cell..." Function Cyclins were originally named because their concentration varies in a cyclical fashion during the cell cycle. (Note that the cyclins are now classified according to their conserved cyclin box structure, and not all these cyclins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclin B
Cyclin B is a member of the cyclin family. Cyclin B is a mitotic cyclin. The amount of cyclin B (which binds to Cdk1) and the activity of the cyclin B-Cdk complex rise through the cell cycle until mitosis, where they fall abruptly due to degradation of cyclin B (Cdk1 is constitutively present). The complex of Cdk and cyclin B is called maturation promoting factor or mitosis promoting factor (MPF). Function Cyclin B is necessary for the progression of the cells into and out of M phase of the cell cycle. At the end of S phase the phosphatase cdc25c dephosphorylates tyrosine15 and this activates the cyclin B/CDK1 complex. Upon activation the complex is shuttled to the nucleus where it serves to trigger for entry into mitosis. However, if DNA damage is detected alternative proteins are activated which results in the inhibitory phosphorylation of cdc25c and therefore cyclinB/CDK1 is not activated. In order for the cell to progress out of mitosis, the degradation of cyclin B i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclin A
Cyclin A is a member of the cyclin family, a group of proteins that function in regulating progression through the cell cycle. The stages that a cell passes through that culminate in its division and replication are collectively known as the cell cycle Since the successful division and replication of a cell is essential for its survival, the cell cycle is tightly regulated by several components to ensure the efficient and error-free progression through the cell cycle. One such regulatory component is cyclin A which plays a role in the regulation of two different cell cycle stages. Types Cyclin A was first identified in 1983 in sea urchin embryos. Since its initial discovery, homologues of cyclin A have been identified in numerous eukaryotes including '' Drosophila'', ''Xenopus'', mice, and in humans but has not been found in lower eukaryotes like yeast. The protein exists in both an embryonic form and somatic form. A single cyclin A gene has been identified in Drosophila while ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John J
John is a common English name and surname: * John (given name) * John (surname) John may also refer to: New Testament Works * Gospel of John, a title often shortened to John * First Epistle of John, often shortened to 1 John * Second Epistle of John, often shortened to 2 John * Third Epistle of John, often shortened to 3 John People * John the Baptist (died ), regarded as a prophet and the forerunner of Jesus Christ * John the Apostle (died ), one of the twelve apostles of Jesus Christ * John the Evangelist, assigned author of the Fourth Gospel, once identified with the Apostle * John of Patmos, also known as John the Divine or John the Revelator, the author of the Book of Revelation, once identified with the Apostle * John the Presbyter, a figure either identified with or distinguished from the Apostle, the Evangelist and John of Patmos Other people with the given name Religious figures * John, father of Andrew the Apostle and Saint Peter * Pope John ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
