4.34 信号接收器-高级
章节大纲
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What pulls a signal in from vast distances?
::甚远处的信号是什么?Some sort of signal receptor. This receptor is usually a embedded in the . Once the signal binds to its receptor, some sort of outcome is initiated - the signal is transferred to the . This may be from an ion channel opening or some other process.
::某种信号受体。 这个受体通常是嵌入在 。 一旦信号与受体连接, 就会启动某种结果 - 信号被传输到 。 这可能是从离子通道打开或其他程序 。Signal Receptors
::信号接收器A signal molecule must bind to its receptor to initiate a response. Receptors are proteins that bind to their signal molecule either externally (cell-surface receptors) or internally (nuclear receptors) within the cytoplasm or . This process is known as signal transduction , and the internal activator is the second messenger . Once a ligand binds to its receptor, a series of reactions are initiated.
::信号分子必须与其受体捆绑,才能启动响应。受体是蛋白质,在外(细胞表面受体)或内(核受体)内(细胞-表面受体)与其信号分子捆绑在一起。这一过程被称为信号感应,内部活化器是第二个送信者。一旦一个离子和它的受体捆绑在一起,就会引发一系列反应。Cell-Surface Receptors
::细胞表面受体Cell-surface receptors are integral membrane proteins—they reach right through the , spanning from the outside to the inside of the cell. These receptor proteins are specific for just one signal molecule. The signaling molecule acts as a ligand when it binds to a receptor protein. A ligand is a small molecule that binds to a larger molecule. Signal molecule binding causes the receptor protein to undergo a conformational change (a change in shape). At this point the receptor protein can interact with another molecule. The ligand (the signal molecule) itself does not pass through the plasma membrane.
::细胞表面受体是内分泌膜的蛋白质——它们从细胞的外向内向右伸展,从细胞的外向内向外。这些受体蛋白只针对一个信号分子。当信号分子与受体蛋白结合时,信号分子的作用是一离子体,当它与受体蛋白结合时,信号分子是一种小分子,与更大的分子结合。信号分子结合使受体蛋白发生相近的变化(形状改变)。此时,受体蛋白可以与另一个分子相互作用。信号分子本身不会通过血浆膜。In eukaryotic cells , most of the intracellular proteins that are activated by a ligand binding to a receptor protein are . Receptor proteins are named after the type of enzyme that they interact with inside the cell. These enzymes include G proteins and protein kinases, likewise there are G-protein-linked receptors and tyrosine kinase receptors. A kinase is a protein involved in phosphorylation. Tyrosine kinase receptors bind many polypeptide growth factors, cytokines , and . Once the ligand is bound, these receptors specifically phosphorylate tyrosine amino acids , activating the signal transduction process inside the cell.
::受体蛋白是以细胞内与其互动的酶类型命名的。这些酶包括G蛋白质和蛋白性动脉酶,同样还有G-蛋白相关受体和亚麻黄素活性受体受体。动脉酶是磷酸化中的一种蛋白质。蒂罗辛血酶受体受体结合了多种聚虫生长因子、cytokines 和 。当受体受体受体受体被约束时,这些受体特别是磷酸丁酸氨基酸,激活细胞内的信号传导过程。A G-protein linked receptor is a receptor that works with the help of a protein called a G-protein. A G-protein gets its name from the molecule to which it is attached, guanosine triphosphate (GTP), or guanosine diphosphate (GDP). The GTP molecule is similar to ATP .
::G-蛋白质连接受体是一种受体,在一种叫做G-蛋白质的蛋白质的帮助下起作用。 G-蛋白质从附着的分子、三磷酸瓜诺辛(GTP)或二磷酸瓜诺辛(guanosine di di 磷酸盐(GDP)获得其名字。 GTP分子与ATP类似。Second Messengers
::第二信使Once G proteins or protein kinase enzymes are activated by a receptor protein - after the ligand binds to its receptor - they create molecules called second messengers. A second messenger is a small molecule that starts a change inside a cell in response to the binding of a specific signal to a receptor protein. Some second messenger molecules include small molecules called cyclic nucleotides , such as cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP). Calcium ions (Ca 2+ ) also act as secondary messengers. Secondary messengers are a part of signal transduction pathways.
::一旦G蛋白质或蛋白质活性体酶被受体蛋白激活 -- -- 在电离层与受体结合后 -- -- 它们就产生名为第二送信员的分子;第二个送信员是小分子,根据受体蛋白特定信号的结合,细胞内开始变化;第二个送信分子包括小分子,称为循环核核素,如环乙烷单磷酸(CAMP)和循环guanosine单色磷酸(cGMP),钙离子(Ca2+)也是二级送信员;二级送信员是信号传输途径的一部分。Two-component signal transduction system. This process begins with the stimulus binding to its receptor. Shown here is a cell-surface receptor. The signal in then transduced to the inside of the cell.
::双构件信号感应系统。 这一过程始于对其受体有约束力的刺激。 这里显示的是细胞表面受体。 然后将信号传送到细胞内部 。Nuclear Receptors
::核接收器Some receptors bind the ligand internally. In this case, the ligand must be able to enter the cell. These receptors usually interact with steroid and thyroid hormones. Once the ligand binds to the receptor, the receptor becomes activated, and the whole complex enters the nucleus, hence these receptors are known as nuclear receptors. In the nucleus, the activated receptor acts as a transcription factor , where it interacts with other proteins to regulate the expression of specific genes , thereby controlling the , , and metabolism of the organism .
::某些受体将离子绑在内部。 在这种情况下, 离子必须能够进入细胞。 这些受体通常与类固醇和甲状腺激素发生相互作用。 一旦离子和甲状腺激素与受体结合, 受体就会被激活, 整个复合体进入核核, 因此这些受体被称为核受体。 在核中, 活性受体作为转录系数, 它与其他蛋白质相互作用, 以调节特定基因的表达, 从而控制生物体的代谢和新陈代谢。Summary
::摘要-
Signal transduction begins with a ligand binding to its receptor.
::信号感应从对其受体的捆绑开始。 -
Cell-surface receptors bind a ligand outside of the cell and internalize the signal, acting through a second messenger.
::细胞表面受体将细胞外的电线捆绑,通过第二个信使将信号内化。 -
Nuclear receptors bind a ligand inside the cell and change transcription of genes by acting as a transcription factor.
::核受体在细胞内捆绑,作为转录系数改变基因转录。
Review
::回顾-
Compare and contrast cell-surface and nuclear receptors.
::比较和对比细胞表层和核受体。 -
What is a second messenger?
::第二个信使是什么? -
What are nuclear receptors functions?
::什么是核受体功能?
Explore More
::探索更多Use this resource to answer the questions that follow.
::使用此资源回答下面的问题 。-
What is a peptide hormone?
::什么是peptide荷尔蒙? -
How does the message from a peptide hormone enter the cell?
::浸泡激素的信息是如何进入细胞的? -
Describe the structure of a G-protein.
::描述 G 蛋白质的结构 。 -
Describe the function of an activated G-protein.
::描述激活的 G 蛋白质的功能 。 -
What is the function of an active phospholipase C?
::活性磷脂C的功能是什么? -
What are the two second messengers discussed in this process?
::在这一过程中,讨论的第二位信使是什么? -
What is the role of an active protein kinase C?
::活蛋白质C的功能是什么?
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Signal transduction begins with a ligand binding to its receptor.
