関連する実験動画
Updated: Aug 11, 2026

09:16
Oligopeptide Competition Assay for Phosphorylation Site Determination
Published on: May 18, 2017
まとめ
腫瘍プロモーターである12-O-テトラデカノイル-ホルボル-13-アセテート (TPA) は,タンパク質キナーゼCを活性化させる.TPAは,42Kタンパク質のチロシンリン酸化も誘導し,TPAにおける役割を示唆する.
科学分野:
- 細胞生物学 細胞生物学
- バイオケミストリー バイオケミストリー
- 腫瘍学 腫瘍学
背景:
- 12-O-テトラデカノイル-ホルボル-13-アセテート (TPA) は,生体内で強力な腫瘍促進剤である.
- TPAはタンパク質キナーゼC (PKC) をインビトロで活性化させ,ダイアシルグリセロルの作用を模倣する.
- PKCはセリンとスレオニン残基の基板をリン酸化する.
研究 の 目的:
- 培養した線維芽細胞にTPAの作用のメカニズムを調査する.
- TPAがチロシンリン酸化によってその効果を媒介するかどうかを判断する.
- TPAに対する反応として,特定の42Kポリペプチドのリン酸化状態を調べる.
主な方法:
- 培養した線維芽細胞をTPAで処理する.
- タイロシン残留物におけるタンパク質リン酸化の分析.
- 外因的に添加されたダイアシルグリセロルの効果の調査.
主要な成果:
- TPA治療は,42,000分子量 (42K) のポリペプチドのチロシンリン酸化を増加させる.
- この42Kポリペプチドは,EGF,PDGF,MSAなどの成長因子に反応してチロシンでリン酸化されます.
- 外因的に添加されたダイアシルグリセロルは,この42Kタンパク質のチロシンリン酸化を刺激します.
結論:
- TPAの腫瘍促進効果には,チロシンリン酸化の誘導が含まれている可能性があります.
- 42Kポリペプチドは,TPA,成長因子,およびダイアシルグリセロールによって誘発されるチロシンリン酸化のための一般的な基質です.
- この発見は,TPA誘発のPKC活性化とチロシンキナーゼシグナル伝達経路を関連付けています.
関連する概念動画
What are Second Messengers?
Because many receptor binding ligands are hydrophilic, they do not cross the cell membrane and thus their message must be relayed to a second messenger on the inside. There are several second messenger pathways, each with their own way of relaying information. G-protein coupled receptors can activate both phosphoinositol and cyclic AMP (cAMP) second messenger pathways. The phosphoinositol path is active when the receptor induces phospholipase C to hydrolyze the phospholipid,...
Phosphorylation
The addition or removal of phosphate groups from proteins is the most common chemical modification that regulates cellular processes. These modifications can affect the structure, activity, stability, and localization of proteins within cells as well as their interactions with other proteins.
During phosphorylation, protein kinases transfer the terminal phosphate group of ATP to specific amino acid side chains of substrate proteins. Serine, threonine, and tyrosine are the most commonly...
During phosphorylation, protein kinases transfer the terminal phosphate group of ATP to specific amino acid side chains of substrate proteins. Serine, threonine, and tyrosine are the most commonly...
Protein Kinases and Phosphatases
Proteins undergo chemical modifications that trigger changes in the charge, structure, and conformation of the proteins. Phosphorylation, acetylation, glycosylation, nitrosylation, ubiquitination, lipidation, methylation, and proteolysis are various protein modifications that regulate protein activity. Such modifications are usually enzyme-driven.
Protein kinases
Many proteins in the cell are regulated by phosphorylation, the addition of a phosphate group. A family of enzymes called kinases...
Protein kinases
Many proteins in the cell are regulated by phosphorylation, the addition of a phosphate group. A family of enzymes called kinases...
Amplifying Signals via Second Messengers
Many receptor binding ligands are hydrophilic; they do not cross the cell membrane but bind to cell-surface receptors. Thus, their message must be relayed by second messengers present in the cell cytoplasm. There are several second messenger pathways, each with its own way of relaying information. For example, the G protein-coupled receptors can activate both phosphoinositol and cyclic AMP (cAMP) second messenger pathways. The phosphoinositol pathway is active when the receptor induces...
Amplifying Signals via Enzymatic Cascade
When a ligand binds to a cell-surface receptor, the receptor's intracellular domain changes shape, which may either activate its enzyme function or allow its binding to other molecules. The initial signal is amplified by most signal transduction pathways. This means that a single ligand molecule can activate multiple molecules of a downstream target. Proteins that relay a signal are most commonly phosphorylated at one or more sites, activating or inactivating the protein. Kinases catalyze the...
IP3/DAG Signaling Pathway
Membrane lipids such as phosphatidylinositol (PI) are precursors for several membrane-bound and soluble second messengers. Specific kinases phosphorylate PI and produce phosphorylated inositol phospholipids. One such inositol phospholipids are the phosphatidylinositol-4,5 bisphosphate [PI(4,5)P2], present in the inner half of the lipid bilayer. Upon ligand binding, GPCR stimulates Gq proteins to turn on phospholipase Cꞵ. Activated phospholipase Cꞵ cleaves PI(4,5)P2 and produces two-second...

