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P21 Activated Kinases
p21 activated kinases (PAKs) are members of a family of enzymes. They serve as targets for the small GTP binding proteins CDC42 and Rac and have been implicated in a wide range of biological activities. Members include: * PAK1, regulating cell motility and morphology * PAK2, possibly playing a role in apoptosis * PAK3, possibly for dendritic development and for the rapid cytoskeletal reorganization in dendritic spines associated with synaptic plasticity * PAK4, a mediator of filopodia formation * PAK5, a mediator of filopodia formation * PAK6 Serine/threonine-protein kinase PAK 6 is an enzyme that in humans is encoded by the ''PAK6'' gene. PAK6 belongs to the Group II PAK family members. Like other family members, PAK6 is also evolutionary conserved across species. Discovery The PAK ..., involved in cytoskeleton rearrangement References External linksPAKInfo with links in thCell Migration Gateway Human proteins {{Protein-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. Almost all metabolic processes in the cell need enzyme catalysis in order to occur at rates fast enough to sustain life. Metabolic pathways depend upon enzymes to catalyze individual steps. The study of enzymes is called ''enzymology'' and the field of pseudoenzyme analysis recognizes that during evolution, some enzymes have lost the ability to carry out biological catalysis, which is often reflected in their amino acid sequences and unusual 'pseudocatalytic' properties. Enzymes are known to catalyze more than 5,000 biochemical reaction types. Other biocatalysts are catalytic RNA molecules, called ribozymes. Enzymes' specificity comes from their unique three-dimensional structures. Like all catalysts, enzymes increase the reaction ra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guanosine Triphosphate
Guanosine-5'-triphosphate (GTP) is a purine nucleoside triphosphate. It is one of the building blocks needed for the synthesis of RNA during the transcription process. Its structure is similar to that of the guanosine nucleoside, the only difference being that nucleotides like GTP have phosphates on their ribose sugar. GTP has the guanine nucleobase attached to the 1' carbon of the ribose and it has the triphosphate moiety attached to ribose's 5' carbon. It also has the role of a source of energy or an activator of substrates in metabolic reactions, like that of ATP, but more specific. It is used as a source of energy for protein synthesis and gluconeogenesis. GTP is essential to signal transduction, in particular with G-proteins, in second-messenger mechanisms where it is converted to guanosine diphosphate (GDP) through the action of GTPases. Uses Energy transfer GTP is involved in energy transfer within the cell. For instance, a GTP molecule is generated by one of the enz ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rac (GTPase)
Rac is a subfamily of the Rho family of GTPases, small (~21 kDa) signaling G proteins (more specifically a GTPase). Just as other G proteins, Rac acts as a molecular switch, remaining inactive while bound to GDP and activated once GEFs remove GDP, permitting GTP to bind. When bound to GTP, Rac is activated. In its activated state, Rac participates in the regulation of cell movement, through its involvement in structural changes to the actin Cytoskeleton. By changing the cytoskeletal dynamics within the cell, Rac-GTPases are able to facilitate the recruitment of neutrophils to the infected tissues, and to regulate degranulation of azurophil and integrin-dependent phagocytosis. Activated Rac also regulates the effector functions of the target proteins involved in downstream signaling. As an essential subunit of NOX2 (NADPH oxidase enzyme complex), Rac is required for ROS (reactive oxygen species) production involved in the formation of NETs (neutrophil extracellular traps, thus, f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PAK1
Serine/threonine-protein kinase PAK 1 is an enzyme that in humans is encoded by the ''PAK1'' gene. PAK1 is one of six members of the PAK family of serine/threonine kinases which are broadly divided into group I (PAK1, PAK2 and PAK3) and group II (PAK4, PAK6 and PAK5/7). The PAKs are evolutionarily conserved. PAK1 localizes in distinct sub-cellular domains in the cytoplasm and nucleus. PAK1 regulates cytoskeleton remodeling, phenotypic signaling and gene expression, and affects a wide variety of cellular processes such as directional motility, invasion, metastasis, growth, cell cycle progression, angiogenesis. PAK1-signaling dependent cellular functions regulate both physiologic and disease processes, including cancer, as PAK1 is widely overexpressed and hyperstimulated in human cancer, at-large. Discovery PAK1 was first discovered as an effector of the Rho GTPases in rat brain by Manser and colleagues in 1994. The human PAK1 was identified as a GTP-dependent interacting partner ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PAK2
Serine/threonine-protein kinase PAK 2 is an enzyme that in humans is encoded by the ''PAK2'' gene. PAK2 is one of three members of Group I PAK family of serine/threonine kinases. The PAKs are evolutionary conserved. PAK2 and its cleaved fragment localize in both the cytoplasmic or nuclear compartments. PAK2 signaling modulates apoptosis, endothelial lumen formation, viral pathogenesis, and cancer including, breast, hepatocarcinoma, and gastric and cancer, at-large. Discovery The human PAK2 was identified as a downstream effector of Rac or Cdc42. Gene and spliced variants The PAK2 gene is about 92.7-kb long. The gene contains 15 exons and generates three alternatively spliced transcripts - two of which code proteins of 524 amino acids and 221 amino acids, while the third one is a 371-bp non-coding RNA transcript(Gene from review) There are two transcripts generated from the murine PAK2 gene, a 5.7-kb transcript coding a 524 amino acids long polypeptide and a 1.2-kb long non ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PAK3
PAK3 (p21-activated kinase 2, beta-PAK) is one of three members of Group I PAK family of evolutionary conserved serine/threonine kinases. PAK3 is preferentially expressed in neuronal cells and involved in synapse formation and plasticity and mental retardation. Discovery PAK3 was initially cloned from a murine fibroblast cDNA library and from a murine embryo cDNA library. Like other group I PAKs, PAK3 is stimulated by activated Cdc42 and Rac1. Gene and spliced variants The human PAK3 gene, the longest group I family member, is 283-kb long. The PAK3 gene is composed of 22 exons of which 6 exons are for 5’-UTR and generates 13 alternative spliced transcripts. Among PAK3 transcripts, 11 transcripts are for coding proteins ranging from 181- to 580-amino acids long, while remaining two transcripts are non-coding RNAs. The murine PAK3 gene contains 10 transcripts, coding six proteins from 544 amino acids and 559 amino acids long, and four smaller polypeptides from 23 to 366 a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PAK4
Serine/threonine-protein kinase PAK 4 is an enzyme that in humans is encoded by the ''PAK4'' gene. PAK4 is one of six members of the PAK family of serine/threonine kinases which are divided into group I (PAK1, PAK2 and PAK3) and group II (PAK4, PAK6 and PAK5/7). PAK4 localizes in sub-cellular domains of the cytoplasm and nucleus. PAK4 regulates cytoskeleton remodeling, phenotypic signaling and gene expression, and affects directional motility, invasion, metastasis, and growth. Similar to PAK1, PAK4-signaling-dependent cellular functions also regulate both physiologic and disease processes such as cancer, as PAK4 is overexpressed and/or hyperstimulated in human cancer, at-large. Discovery PAK4, the founding member of Group II PAK member, was cloned and identified by Minden A. and colleagues in 1998 using a PCR-based strategy from a cDNA library prepared from Jurkett cells. Gene and spliced variants The group II PAKs have less coding exons compared with group I PAKs, highlights ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PAK5
Serine/threonine-protein kinase PAK 5 is an enzyme that in humans is encoded by the ''PAK5'' gene. The PAK5 enzyme is one of three members of Group II PAK family of serine/threonine kinases, and evolutionary conserved across species. Discovery The PAK5 was initially cloned as a brain-specific kinase with a predominant expression in brain with a suggested role in neurite growth in neuronal cells. Selectivity of PAK5 signaling was recognized by its ability to stimulate the JNK kinase but not p38 or ERK kinases. Gene and spliced variants The PAK5 gene, the longest among the PAK family, contains a total of 12 exons of which four exons are for 5’-UTR and remaining 8 exons for protein coding(Gene from review). Alternative exon splicing of the PAK5 gene generates three transcripts, and one of the transcript encodes a 719 amino acids long protein(Gene from review). The exon splicing of the murine PAK5 gene generates three transcripts, two of which code an identical 719 amin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PAK6
Serine/threonine-protein kinase PAK 6 is an enzyme that in humans is encoded by the ''PAK6'' gene. PAK6 belongs to the Group II PAK family members. Like other family members, PAK6 is also evolutionary conserved across species. Discovery The PAK6 was originally cloned as an androgen receptor interacting kinase which can be stimulated by androgen receptor but not Rac or Cdc42, like other family members. Gene and spliced variants The human PAK6 gene consists of 16 exons of which 8 exons are used for 5’-UTR splicing to generating 17 transcripts by alternative splicing, and the gene is about 38-kb long. Among PAK6 transcripts, 14 are protein coding RNAs to code four proteins of 681 and 636 amino acids while remaining PAK6 transcripts are non-coding RNAs. There are five transcripts in murine PAK6 gene, of which two transcripts are protein coding and other two non-coding RNAs(Gene from review). Protein domains Following the general structural organization of the group II PAKs, P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
