広義には細胞がん化を誘導する作用をもつ遺伝子。狭義にはレトロウイルスのがん遺伝子およびそれに対応する細胞側遺伝子を指し、それ以外のがん化誘導遺伝子をトランスホーミング遺伝子と呼ぶ。
動物に感染し，急性の腫瘍形成を誘導するRNAがんウイルスのゲノム中に腫瘍形成に必須の遺伝子が見出された。（ラウス肉腫ウイルスのsrc遺伝子）その後、様々なウイルスからがん遺伝子が見つかったが、それらは正常細胞染色体上の遺伝子が発がん能の弱いRNAウイルスに取り込まれ、変異によりがん可能をもつようになったと考えられる。
増殖因子
- sis（サル肉腫ウイルス）
- 血小板由来増殖因子（PDGF β鎖）
Platelet-derived growth factor subunit B
Short name=PDGF subunit B
- Alternative name(s):PDGF-2
- Platelet-derived growth factor B chain
- Platelet-derived growth factor beta polypeptide
- Proto-oncogene c-Sis
- INN=Becaplermin
Gene names
- Name: PDGFB
- Synonyms: PDGF2, SIS
Function
胎児の発生、細胞の増殖、移動、生存、走化性に重要な役割をもつ。間葉系細胞の強力な増殖促進因子。正常な増殖に必須で、血管周囲の細胞や血管平滑筋細胞、中枢神経系、皮膚、肺、心臓や胎盤で。正常な血管の発達、腎臓の糸球体の発達。創傷治癒、
Growth factor that plays an essential role in the regulation of embryonic development, cell proliferation, cell migration, survival and chemotaxis. Potent mitogen for cells of mesenchymal origin. Required for normal proliferation and recruitment of pericytes and vascular smooth muscle cells in the central nervous system, skin, lung, heart and placenta. Required for normal blood vessel development, and for normal development of kidney glomeruli. Plays an important role in wound healing. Signaling is modulated by the formation of heterodimers with PDGFA By similarity.
Subunit structure
Homodimer; antiparallel disulfide-linked dimer. Heterodimer with PDGFA; antiparallel disulfide-linked dimer. The PDGFB homodimer interacts with PDGFRA and PDGFRB homodimers, and with heterodimers formed by PDGFRA and PDGFRB. The heterodimer composed of PDGFA and PDGFB interacts with PDGFRB homodimers, and with heterodimers formed by PDGFRA and PDGFRB. Interacts with XLKD1 By similarity. Ref.19 Ref.24
Subcellular location
Secreted. Note: Released by platelets upon wounding.
Tissue specificity
Expressed at high levels in the heart, brain (sustantia nigra), placenta and fetal kidney. Expressed at moderate levels in the brain (hippocampus), skeletal muscle, kidney and lung. Ref.20
Involvement in disease
Basal ganglia calcification, idiopathic, 5 (IBGC5) [MIM:615483]: A form of basal ganglia calcification, an autosomal dominant condition characterized by symmetric calcification in the basal ganglia and other brain regions. Affected individuals can either be asymptomatic or show a wide spectrum of neuropsychiatric symptoms, including parkinsonism, dystonia, tremor, ataxia, dementia, psychosis, seizures, and chronic headache. Serum levels of calcium, phosphate, alkaline phosphatase and parathyroid hormone are normal. The neuropathological hallmark of the disease is vascular and pericapillary calcification, mainly of calcium phosphate, in the affected brain areas.
Note: The disease is caused by mutations affecting the gene represented in this entry. Ref.21 Ref.25
A chromosomal aberration involving PDGFB is found in dermatofibrosarcoma protuberans. Translocation t(17;22)(q22;q13) with PDGFB. Ref.21
Pharmaceutical use
Available under the name Regranex (Ortho-McNeil). Used to promote healing in diabetic neuropathic foot ulcers.
Sequence similarities
Belongs to the PDGF/VEGF growth factor family.
受容体チロシンキナーゼ
- erbB（トリ赤芽球性白血病ウイルス）
- 上皮増殖因子受容体（EGFR）
- kit
- マクロファージコロニー刺激因子（M-CSF）血小板由来増殖因子（PDGF）の受容体と良く似ている。
非受容体チロシンキナーゼ
- src（ラウストリ肉腫ウイルス）
- シグナル伝達系・細胞接着
- Function
- Non-receptor protein tyrosine kinase which is activated following engagement of many different classes of cellular receptors including immune response receptors, integrins and other adhesion receptors, receptor protein tyrosine kinases, G protein-coupled receptors as well as cytokine receptors. （免疫反応、インテグリンや他の接着分子、受容体のチロシンキナーゼ、Ｇタンパク質共役型受容体やサイトカイン受容体など多くのことなるクラスの受容体の連動に続く活性化）Participates in signaling pathways that control a diverse spectrum of biological activities including gene transcription, immune response, cell adhesion, cell cycle progression, apoptosis, migration, and transformation. （転写、免疫応答、細胞接着、細胞周期、アポトーシス、細胞の移動、がん化など幅広い生命現象に係わるシグナル伝達に関与する）Due to functional redundancy between members of the SRC kinase family, identification of the specific role of each SRC kinase is very difficult.（Srcキナーゼファミリーは重複しており、それぞれの機能を同定するのは困難） SRC appears to be one of the primary kinases activated following engagement of receptors and plays a role in the activation of other protein tyrosine kinase (PTK) families.（受容体の連動に引き続き活性化される最初のキナーゼのひとつで、他のチロシンキナーゼファミリーの活性化で重要な役割をもつ） Receptor clustering or dimerization leads to recruitment of SRC to the receptor complexes where it phosphorylates the tyrosine residues within the receptor cytoplasmic domains.（受容体の集合や二量体化はSRCの受容体の細胞質ドメインのチロシン残基のリン酸化する場所にSRCが加わる） Plays an important role in the regulation of cytoskeletal organization through phosphorylation of specific substrates such as AFAP1. Phosphorylation of AFAP1 allows the SRC SH2 domain to bind AFAP1 and to localize to actin filaments. Cytoskeletal reorganization is also controlled through the phosphorylation of cortactin (CTTN). When cells adhere via focal adhesions to the extracellular matrix, signals are transmitted by integrins into the cell resulting in tyrosine phosphorylation of a number of focal adhesion proteins, including PTK2/FAK1 and paxillin (PXN). In addition to phosphorylating focal adhesion proteins, SRC is also active at the sites of cell-cell contact adherens junctions and phosphorylates substrates such as beta-catenin (CTNNB1), delta-catenin (CTNND1), and plakoglobin (JUP). Another type of cell-cell junction, the gap junction, is also a target for SRC, which phosphorylates connexin-43 (GJA1). SRC is implicated in regulation of pre-mRNA-processing and phosphorylates RNA-binding proteins such as KHDRBS1. Also plays a role in PDGF-mediated tyrosine phosphorylation of both STAT1 and STAT3, leading to increased DNA binding activity of these transcription factors. Involved in the RAS pathway through phosphorylation of RASA1 and RASGRF1. Plays a role in EGF-mediated calcium-activated chloride channel activation. Required for epidermal growth factor receptor (EGFR) internalization through phosphorylation of clathrin heavy chain (CLTC and CLTCL1) at 'Tyr-1477'. Involved in beta-arrestin (ARRB1 and ARRB2) desensitization through phosphorylation and activation of ADRBK1, leading to beta-arrestin phosphorylation and internalization. Has a critical role in the stimulation of the CDK20/MAPK3 mitogen-activated protein kinase cascade by epidermal growth factor. Might be involved not only in mediating the transduction of mitogenic signals at the level of the plasma membrane but also in controlling progression through the cell cycle via interaction with regulatory proteins in the nucleus. Plays an important role in osteoclastic bone resorption in conjunction with PTK2B/PYK2. Both the formation of a SRC-PTK2B/PYK2 complex and SRC kinase activity are necessary for this function. Recruited to activated integrins by PTK2B/PYK2, thereby phosphorylating CBL, which in turn induces the activation and recruitment of phosphatidylinositol 3-kinase to the cell membrane in a signaling pathway that is critical for osteoclast function. Promotes energy production in osteoclasts by activating mitochondrial cytochrome C oxidase. Phosphorylates DDR2 on tyrosine residues, thereby promoting its subsequent autophosphorylation. Phosphorylates RUNX3 and COX2 on tyrosine residues, TNK2 on 'Tyr-284' and CBL on 'Tyr-731'. Enhances DDX58/RIG-I-elicited antiviral signaling. Phosphorylates PDPK1 at 'Tyr-9', 'Tyr-373' and 'Tyr-376'. Phosphorylates BCAR1 at 'Tyr-128'. Phosphorylates CBLC at multiple tyrosine residues, phosphorylation at 'Tyr-341' activates CBLC E3 activity.
セリン・トレオニンキナーゼ
- akt（マウス胸腺腫ウイルス）
- PI3キナーゼなどシグナル伝達系
ホスファチジルイノシトール3-キナーゼを介して活性化される。Ｎ末端にPHドメイン、Ｃ末端にキナーゼドメインをもつ。プロテインキナーゼＡ、プロテインキナーゼＣとの相同性をもとに分離されたので、RAC (Related to PKA and PKC)あるいはプロテインキナーゼＢと呼ばれる。ウイルス性がん遺伝子v-aktのがん原遺伝子として同定されたことからAktとも呼ばれる。
RAC-alpha serine/threonine-protein kinase
EC=2.7.11.1
Alternative name(s):
Protein kinase B
Short name=PKB
Protein kinase B alpha
Short name=PKB alpha
Proto-oncogene c-Akt
RAC-PK-alpha
Gene names
Name: AKT1
Synonyms: PKB, RAC
- Function
- 類縁の三種類のキナーゼのひとつ。代謝、増殖、生存、成長、血管新生などに係わる。100を超えるリン酸化の基質が知られている。Aktはインスリンにより誘導されるSLC2A4/GLUT4の細胞膜への移動によるグルコース取り込みの調節に係わる。AKT1 is one of 3 closely related serine/threonine-protein kinases (AKT1, AKT2 and AKT3) called the AKT kinase, and which regulate many processes including metabolism, proliferation, cell survival, growth and angiogenesis. This is mediated through serine and/or threonine phosphorylation of a range of downstream substrates. Over 100 substrate candidates have been reported so far, but for most of them, no isoform specificityhas been reported. AKT is responsible of the regulation of glucose uptake by mediating insulin-induced translocation of the SLC2A4/GLUT4 glucose transporter to the cell surface. Phosphorylation of PTPN1 at 'Ser-50' negatively modulates its phosphatase activity preventing dephosphorylation of the insulin receptor and the attenuation of insulin signaling. Phosphorylation of TBC1D4 triggers the binding of this effector to inhibitory 14-3-3 proteins, which is required for insulin-stimulated glucose transport. AKT regulates also the storage of glucose in the form of glycogen by phosphorylating GSK3A at 'Ser-21' and GSK3B at 'Ser-9', resulting in inhibition of its kinase activity. Phosphorylation of GSK3 isoforms by AKT is also thought to be one mechanism by which cell proliferation is driven. AKT regulates also cell survival via the phosphorylation of MAP3K5 (apoptosis signal-related kinase). Phosphorylation of 'Ser-83' decreases MAP3K5 kinase activity stimulated by oxidative stress and thereby prevents apoptosis. AKT mediates insulin-stimulated protein synthesis by phosphorylating TSC2 at 'Ser-939' and 'Thr-1462', thereby activating mTORC1 signaling and leading to both phosphorylation of 4E-BP1 and in activation of RPS6KB1. AKT is involved in the phosphorylation of members of the FOXO factors (Forkhead family of transcription factors), leading to binding of 14-3-3 proteins and cytoplasmic localization. In particular, FOXO1 is phosphorylated at 'Thr-24', 'Ser-256' and 'Ser-319'. FOXO3 and FOXO4 are phosphorylated on equivalent sites. AKT has an important role in the regulation of NF-kappa-B-dependent gene transcription and positively regulates the activity of CREB1 (cyclic AMP (cAMP)-response element binding protein). The phosphorylation of CREB1 induces the binding of accessory proteins that are necessary for the transcription of pro-survival genes such as BCL2 and MCL1. AKT phosphorylates 'Ser-454' on ATP citrate lyase (ACLY), thereby potentially regulating ACLY activity and fatty acid synthesis. Activates the 3B isoform ofcyclic nucleotide phosphodiesterase (PDE3B) via phosphorylation of 'Ser-273', resulting in reduced cyclic AMP levels and inhibition of lipolysis. Phosphorylates PIKFYVE on 'Ser-318', which results in increased PI3P-5 activity. The Rho GTPase-activating protein DLC1 is another substrate and its phosphorylation is implicated in the regulation cell proliferation and cell growth. AKT plays a role as key modulator of the AKT-mTOR signaling pathway controlling the tempo of the process of newborn neurons integration during adult neurogenesis, including correct neuron positioning, dendritic development and synapse formation. Signals downstream of phosphatidylinositol 3-kinase (PI3K) to mediate the effects of various growth factors such as platelet-derived growth factor (PDGF), epidermal growth factor (EGF), insulin and insulin-like growth factor I (IGF-I). AKT mediates the antiapoptotic effects of IGF-I. Essential for the SPATA13-mediated regulation of cell migration and adhesion assembly and disassembly. May be involved in the regulation of the placental development. Phosphorylates STK4/MST1 at 'Thr-120' and 'Thr-387' leading to inhibition of its: kinase activity, nuclear translocation, autophosphorylation and ability to phosphorylate FOXO3. Phosphorylates STK3/MST2 at 'Thr-117' and 'Thr-384' leading to inhibition of its: cleavage, kinase activity, autophosphorylation at Thr-180, binding to RASSF1 and nuclear translocation. Phosphorylates SRPK2 and enhances its kinase activity towards SRSF2 and ACIN1 and promotes its nuclear translocation. Phosphorylates RAF1 at 'Ser-259' and negatively regulates its activity. Phosphorylation of BAD stimulates its pro-apoptotic activity. Phosphorylates KAT6A at 'Thr-369' and this phosphorylation inhibits the interaction of KAT6A with PML and negatively regulates its acetylation activity towards p53/TP53. Ref.6 Ref.8 Ref.11 Ref.12 Ref.13 Ref.14 Ref.17 Ref.19 Ref.20 Ref.22 Ref.24 Ref.25 Ref.32 Ref.35 Ref.38 Ref.40 Ref.41 Ref.44 Ref.45 Ref.47 Ref.48 Ref.49 Ref.50 Ref.51 Ref.52 Ref.65
AKT1-specific substrates have been recently identified, including palladin (PALLD), which phosphorylation modulates cytoskeletal organization and cell motility; prohibitin (PHB), playing an important role in cell metabolism and proliferation; and CDKN1A, for which phosphorylation at 'Thr-145' induces its release from CDK2 and cytoplasmic relocalization. These recent findings indicate that the AKT1 isoform hasa more specific role in cell motility and proliferation. Phosphorylates CLK2 thereby controlling cell survival to ionizing radiation. Ref.6 Ref.8 Ref.11 Ref.12 Ref.13 Ref.14 Ref.17 Ref.19 Ref.20 Ref.22 Ref.24 Ref.25 Ref.32 Ref.35 Ref.38 Ref.40 Ref.41 Ref.44 Ref.45 Ref.47 Ref.48 Ref.49 Ref.50 Ref.51 Ref.52 Ref.65
Enzyme regulation
Three specific sites, one in the kinase domain (Thr-308) and the two other ones in the C-terminal regulatory region (Ser-473 and Tyr-474), need to be phosphorylated for its full activation. Inhibited by pyrrolopyrimidine inhibitors like aniline triazole and spiroindoline. Ref.9 Ref.11 Ref.68 Ref.69 Ref.70 Ref.72
Subunit structure
Interacts (via the C-terminus) with CCDC88A (via its C-terminus). Interacts with GRB10; the interaction leads to GRB10 phosphorylation thus promoting YWHAE-binding By similarity. Interacts with AGAP2 (isoform 2/PIKE-A);the interaction occurs in the presence of guanine nucleotides. Interacts with AKTIP. Interacts (via PH domain) with MTCP1, TCL1A AND TCL1B. Interacts with CDKN1B; the interaction phosphorylates CDKN1B promoting 14-3-3 binding and cell-cycle progression. Interacts with MAP3K5 and TRAF6. Interacts with BAD, PPP2R5B, STK3 and STK4. Interacts (via PH domain) with SIRT1. Interacts with SRPK2 in a phosphorylation-dependent manner. Interacts with RAF1. Interacts with TRIM13; the interaction ubiquitinates AKT1 leading to its proteasomal degradation. Interacts with TNK2 and CLK2. Interacts (via the C-terminus) with THEM4 (via its C-terminus). Interacts with and phosphorylated by PDPK1. Ref.13 Ref.14 Ref.15 Ref.16 Ref.17 Ref.18 Ref.20 Ref.23 Ref.24 Ref.26 Ref.29 Ref.30 Ref.32 Ref.35 Ref.39 Ref.40 Ref.44 Ref.46 Ref.47 Ref.49 Ref.51 Ref.52 Ref.54 Ref.55 Ref.62 Ref.64 Ref.66 Ref.67
Subcellular location
Cytoplasm. Nucleus. Cell membrane. Note: Nucleus after activation by integrin-linked protein kinase 1 (ILK1). Nuclear translocation is enhanced by interaction with TCL1A. Phosphorylation on Tyr-176 by TNK2 results in its localization to the cell membrane where it is targeted for further phosphorylations on Thr-308 and Ser-473 leading to its activation and the activated form translocates to the nucleus. Ref.18 Ref.39 Ref.52 Ref.64
Tissue specificity
Expressed in prostate cancer and levels increase from the normal to the malignant state (at protein level). Expressed in all human cell types so far analyzed. The Tyr-176 phosphorylated form shows a significant increase in expression in breast cancers during the progressive stages i.e. normal to hyperplasia (ADH), ductal carcinoma in situ (DCIS), invasive ductal carcinoma (IDC) and lymph node metastatic (LNMM) stages. Ref.6 Ref.39 Ref.52
Domain
Binding of the PH domain to phosphatidylinositol 3,4,5-trisphosphate (PI(3,4,5)P3) following phosphatidylinositol 3-kinase alpha (PIK3CA) activity results in its targeting to the plasma membrane. The PH domain mediates interaction with TNK2 and Tyr-176 is also essential for this interaction.
The AGC-kinase C-terminal mediates interaction with THEM4.
Post-translational modification
O-GlcNAcylation at Thr-305 and Thr-312 inhibits activating phosphorylation at Thr-308 via disrupting the interaction between AKT1 and PDPK1. O-GlcNAcylation at Ser-473 also probably interferes with phosphorylation at this site.
Phosphorylation on Thr-308, Ser-473 and Tyr-474 is required for full activity. Activated TNK2 phosphorylates it on Tyr-176 resulting in its binding to the anionic plasma membrane phospholipid PA. This phosphorylated form localizes to the cell membrane, where it is targeted by PDPK1 and PDPK2 for further phosphorylations on Thr-308 and Ser-473 leading to its activation. Ser-473 phosphorylation by mTORC2 favors Thr-308 phosphorylation by PDPK1. Phosphorylated at Thr-308 and Ser-473 by IKBKE and TBK1. Ser-473 phosphorylation is enhanced by interaction with AGAP2 isoform 2(PIKE-A). Ser-473 phosphorylation is enhanced in focal cortical dysplasias with Taylor-type balloon cells. Ser-473 phosphorylation is enhanced by signaling through activated FLT3. Dephosphorylated at Thr-308 and Ser-473 by PP2A phosphatase. The phosphorylated form of PPP2R5B is required for bridging AKT1 with PP2A phosphatase. Ref.9 Ref.10 Ref.11 Ref.21 Ref.26 Ref.27 Ref.31 Ref.33 Ref.34 Ref.52 Ref.55 Ref.58 Ref.61 Ref.68 Ref.70
Ubiquitinated via 'Lys-48'-linked polyubiquitination by ZNRF1, leading to its degradation by the proteasome By similarity. Ubiquitinated; undergoes both 'Lys-48'- and 'Lys-63'-linked polyubiquitination. TRAF6-induced 'Lys-63'-linked AKT1 ubiquitination is critical for phosphorylation and activation. When ubiquitinated, it translocates to the plasma membrane, where it becomes phosphorylated. When fully phosphorylated and translocated into the nucleus, undergoes 'Lys-48'-polyubiquitination catalyzed by TTC3, leading to its degradation by the proteasome. Also ubiquitinated by TRIM13 leading to its proteasomal degradation. Phosphorylated, undergoes 'Lys-48'-linked polyubiquitination preferentially at Lys-284 catalyzed by MUL1, leading to its proteasomal degradation. Ref.9 Ref.10 Ref.11 Ref.21 Ref.26 Ref.27 Ref.31 Ref.33 Ref.34 Ref.52 Ref.55 Ref.58 Ref.61 Ref.68 Ref.70
Acetylated on Lys-14 and Lys-20 by the histone acetyltransferases EP300 and KAT2B. Acetylation results in reduced phosphorylation and inhibition of activity. Deacetylated at Lys-14 and Lys-20 by SIRT1. SIRT1-mediated deacetylation relieves the inhibition. Ref.62
***Involvement in disease
Breast cancer (BC) [MIM:114480]: A common malignancy originating from breast epithelial tissue. Breast neoplasms can be distinguished by their histologic pattern. Invasive ductal carcinoma is by far the most common type. Breast cancer is etiologically and genetically heterogeneous. Important genetic factors have been indicated by familial occurrence and bilateral involvement. Mutations at more than one locus can be involved in different families or even in the same case.
Note: Disease susceptibility is associated with variations affecting the gene represented in this entry.
Colorectal cancer (CRC) [MIM:114500]: A complex disease characterized by malignant lesions arising from the inner wall of the large intestine (the colon) and the rectum. Genetic alterations are often associated with progression from premalignant lesion (adenoma) to invasive adenocarcinoma. Risk factors for cancer of the colon and rectum include colon polyps, long-standing ulcerative colitis, and genetic family history.
Note: The gene represented in this entry may be involved in disease pathogenesis.
Genetic variations in AKT1 may play a role in susceptibility to ovarian cancer.
Proteus syndrome (PROTEUSS) [MIM:176920]: A highly variable, severe disorder of asymmetric and disproportionate overgrowth of body parts, connective tissue nevi, epidermal nevi, dysregulated adipose tissue, and vascular malformations. Many features of Proteus syndrome overlap with other overgrowth syndromes.
Note: The disease is caused by mutations affecting the gene represented in this entry. Ref.74 Ref.75
Cowden syndrome 6 (CWS6) [MIM:615109]: A form of Cowden syndrome, a hamartomatous polyposis syndrome with age-related penetrance. Cowden syndrome is characterized by hamartomatous lesions affecting derivatives of ectodermal, mesodermal and endodermal layers, macrocephaly, facial trichilemmomas (benign tumors of the hair follicle infundibulum), acral keratoses, papillomatous papules, and elevated risk for development of several types of malignancy, particularly breast carcinoma in women and thyroid carcinoma in both men and women. Colon cancer and renal cell carcinoma have also been reported. Hamartomas can be found in virtually every organ, but most commonly in the skin, gastrointestinal tract, breast and thyroid.
Note: The disease is caused by mutations affecting the gene represented in this entry.
Sequence similarities
Belongs to the protein kinase superfamily. AGC Ser/Thr protein kinase family. RAC subfamily.
Contains 1 AGC-kinase C-terminal domain.
Contains 1 PH domain.
Contains 1 protein kinase domain.
