Protein targeting
From Wikipedia, the free encyclopedia
This article deals with protein targeting in eukaryotes except where noted.
Protein targeting or protein sorting is the biological mechanism by which proteins are transported to the appropriate destinations in the cell or outside of it. Proteins can be targeted to the inner space of an organelle, different intracellular membranes, plasma membrane, or to exterior of the cell via secretion. This delivery process is carried out based on information contained in the protein itself. Correct sorting is crucial for the cell; errors can lead to diseases. 靶向蛋白
维基百科，自由的百科全书
这篇文章除了注意的地方在真核生物蛋白靶向交易。
蛋白靶向或蛋白质排序是通过该蛋白质运输到细胞中的相应的目的地或它的外部的生物机制。蛋白质可靶向至细胞器，不同细胞内膜，质膜的内部空间，或通过分泌细胞的外部。这个输送过程是基于包含在该蛋白质本身的信息进行的。正确的排序是细胞的关键;错误可以导致疾病的发生。Targeting signals
Targeting signals are the pieces of information that enable the cellular transport machinery to correctly position a protein inside or outside the cell. This information is contained in the polypeptide chain or in the folded protein. The continuous stretch of amino acid residues in the chain that enables targeting are called signal peptides or targeting peptides. There are two types of targeting peptides, the presequences and the internal targeting peptides. The presequences of the targeting peptide are often found at the N-terminal extension and is composed of between 6-136 basic and hydrophobic amino acids. In case of peroxisomes the targeting sequence is on the C-terminal extension mostly. Other signals, known as signal patches, are composed of parts which are separate in the primary sequence. They become functional when folding brings them together on the protein surface. In addition, protein modifications like glycosylations can induce targeting.
靶向信号
定位信号是使蜂窝运输机械正确定位内或细胞外的蛋白质的信息块。此信息包含在该多肽链，或在折叠的蛋白质。的链中的氨基酸残基使得能够针对连续拉伸称为信号肽或靶向肽。有两种类型的靶向肽的前序列和内部靶向肽。所述靶向肽的前序列常常发现在N-端延伸，并6-136基本和疏水氨基酸之间组成。在过氧化物酶的情况下，靶向序列是在
C-末端延伸居多。其他信号，称
为信号贴剂，是由它们在一级序列分开的零件。当折叠使他们在一起蛋白质表面上他们变得功能。此外，像糖基化蛋白修饰可诱发靶向。
Protein translocation
In 1970, Günter Blobel conducted experiments on the translocation of proteins across membranes. He was awarded the 1999 Nobel prize for his findings. He discovered that many proteins have a signal sequence, that is, a short amino acid sequence at one end that functions like a postal code for the target organelle. The translation of mRNA into protein by a ribosome takes place within the cytosol. If the synthesized proteins \organelle, they can be transported there in either of two ways depending on the protein: Co-translational translocation (translocation during the process of translation), and Post-translational translocation(translocation after the process of translation is complete).
蛋白质易位
在1970年，古特·布洛伯尔上跨膜蛋白的易位进行的实验。他被授予1999年诺贝尔文学奖，他的研究结果。他发现，许多蛋白具有信号序列，也就是说，在一端具有短的氨基酸序列，像对靶细胞器邮政编码功能。
mRNA的核糖体翻译成蛋白质发生细胞
质内进行。共翻译转运（易位翻译的过程中），和翻译后转运（处
理之后易位：如果合成的蛋白质“属于”在不同的细胞器，它们可以有以下两种方式取决于蛋白质上运翻译完成）。Co-translational translocation
Most proteins that are secretory, membrane-bound, or reside in the endoplasmic reticulum (ER), golgi or endosomes use the co-translational translocation pathway. This process begins with the N-terminal signal peptide of the protein being recognized by a signal recognition particle (SRP) while the protein is still being synthesized on the ribosome. The synthesis pauses while the ribosome-protein complex is transferred to an SRP receptor on the ER in eukaryotes, and the plasma membrane in prokaryotes. There, the nascent protein is inserted into the translocon, a membrane-bound protein conducting channel composed of the Sec61 translocation complex in eukaryotes, and the homologous SecYEG complex in prokaryotes. In secretory proteins and type I transmembrane proteins, the signal sequence is immediately cleaved from the nascent polypeptide once it has been translocated into the membrane of the ER (eukaryotes) or plasma membrane (prokaryotes) by signal peptidase. The signal sequence of type II membrane proteins and some membrane proteins are not cleaved off and therefore are referred to as signal anchor sequences. Within the ER, the protein is first covered by a chaperone protein to protect it from the high concentration of other proteins in the ER,
giving it time to fold correctly. Once folded, the protein is modified as needed (for example, by glycosylation), then transported to the Golgi for further processing and goes to its target organelles or is retained in the ER by various ER retention mechanisms.
共翻译转运
是分泌大多数蛋白，膜结合，或驻留在内质网（
ER），高尔基
N-末端信
体或内体使用共翻译转运途径。此过程开始于该蛋白的
号肽由信号识别颗粒（SRP）所识别，而蛋白质仍在核糖体上合成的。而核糖体蛋白复合物被转移到在真核生物内质网的
SRP受体，
并在原核生物质膜合成暂停。那里，初生蛋白插入位子，在真核生物的Sec61易位复合物组成的膜结合蛋白导电通道，而在原核生物同源SecYEG复杂。在分泌蛋白和I型跨膜蛋白，信号序列被立即从新生多肽裂解一旦已转运到内质网（真核生物）或质膜（原核生物）由信号肽酶的膜。
II型膜蛋白和一些膜蛋白的信号
序列不裂解，因此作为信号锚定序列被称作。内质网，蛋白质首先被伴侣蛋白覆盖，以保护其免受在ER其它蛋白质的高浓度，给它的时间来正确地折叠。一旦折叠，蛋白质根据需要修改（例如，通过糖基化），然后运到高尔基体进行进一步的处理，然后进到它的靶细胞器或保持在通过各种
ER滞留机制对ER
The amino acid chain of transmembrane proteins, which often are transmembrane receptors, passes through a membrane one or several times. They are inserted into the membrane by translocation,
Proteintargeting靶向蛋白讲解(20201005143805)
