ヘッジホッグの応答ネットワーク:センサー,スイッチ,ルーター
Lawrence Lum1, Philip A Beachy
1Department of Molecular Biology and Genetics, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
まとめ
ヘッジホッグ (Hh) 信号経路は,細胞の成長と発達を制御する. 新しい発見は,キネシンモータータンパク質が,細胞膜から細胞プラズマにHh信号を伝達し,経路の活性化に影響を及ぼす上で不可欠であることを明らかにしています.
科学分野:
- 細胞生物学 細胞生物学
- 分子生物学は分子生物学である.
- 発達生物学 発達生物学とは
背景:
- ヘッジホッグ (Hh) 信号伝達経路は,胚の発達,組織ホメオスタシス,がんにおいて重要な役割を果たします.
- Hhシグナル伝達の調節不良は,腫瘍の発症と進行に関与しています.
- Hh信号伝導の理解は,治療的介入に不可欠です.
研究 の 目的:
- Hh信号伝導の新たなメカニズムを解明する.
- Hh経路に関与する新しいコンポーネントを特定する.
- 経路の活性化におけるスムージングの役割を特徴づける.
主な方法:
- Smoothenedと細胞内信号構成要素の相互作用を調査した.
- Hhシグナル伝達に関与するタンパク質複合体を特定するために生化学的測定を用いた.
- 細胞モデルにおける特定された経路成分の機能を調査した.
主要な成果:
- Hh信号伝達の重要な媒介体として非典型のキネシンを特定しました.
- Smoothenedが信号伝播を促進するためにこのキネシンを採用することを実証しました.
- 転写因子Ciを含む複合体とのキネシンの相互作用を特徴づけた.
結論:
- アチピカルキネシンは,Hh信号経路の新しい成分です.
- 信号伝達は,膜から細胞質へのキネシン媒介による輸送を伴う.
- このメカニズムは,Hh経路の調節と潜在的な治療目標に関する新しい洞察を提供します.
関連する概念動画
Signal Transduction: Overview
Cells respond to many types of information, often through receptor proteins positioned on the membrane. They respond to chemical signals, such as hormones, neurotransmitters, and other signaling molecules, initiating a series of molecular reactions to produce an appropriate response. This is called signal transduction. Cells also coordinate different responses elicited by the same signaling molecule via mediators, allowing molecular cross-talk.
Typically, signal transduction involves three...
Typically, signal transduction involves three...
Network Function of a Circuit
Frequency response analysis in electrical circuits provides vital insights into a circuit's behavior as the frequency of the input signal changes. The transfer function, a mathematical tool, is instrumental in understanding this behavior. It defines the relationship between phasor output and input and comes in four types: voltage gain, current gain, transfer impedance, and transfer admittance. The critical components of the transfer function are the poles and zeros.
Overcurrent Relays
Overcurrent relays, crucial for circuit protection, are connected to the secondary current of a current transformer. There are two primary types of overcurrent relays: instantaneous and time-delay.
Instantaneous overcurrent relays activate immediately when the input current exceeds a predetermined value, known as the pickup current, instantly energizing the circuit breaker trip coil. This rapid response is vital for addressing severe faults quickly.
Time-delay overcurrent relays, on the other...
Instantaneous overcurrent relays activate immediately when the input current exceeds a predetermined value, known as the pickup current, instantly energizing the circuit breaker trip coil. This rapid response is vital for addressing severe faults quickly.
Time-delay overcurrent relays, on the other...
Reclosers and Fuses
Automatic circuit reclosers enhance the protection of distribution circuits by interrupting and auto-reclosing an AC circuit according to a preset sequence. They effectively manage temporary faults on overhead distribution lines, often caused by tree limbs or wildlife, by briefly disrupting service to improve overall reliability. However, contact with reclosers or energized broken conductors on the ground can pose serious hazards.
A comprehensive protection scheme for radial distribution...
A comprehensive protection scheme for radial distribution...
Line Protection with Impedance Relays
Coordinating time-delay overcurrent relays in complex radial systems and directional overcurrent relays in multi-source transmission loops can be challenging. Impedance relays address these issues by responding to the voltage-to-current ratio, specifically measuring the apparent impedance of a line. These relays become more sensitive during faults as current increases and voltage decreases, thereby reducing the apparent impedance.
Under normal conditions, low load currents keep the measured...
Under normal conditions, low load currents keep the measured...
Pilot and Numeric Relaying
Pilot relaying is a type of differential protection used in power systems. It compares electrical quantities at the terminals of equipment via a communication channel instead of direct relay interconnection. This method is essential for transmission lines where the terminals are far apart, typically up to 80 km for lines with 69 to 115 kV ratings. Four types of communication channels are used for pilot relaying:


