G蛋白连接受体和酶连接受体之间的差异

Thekey difference在G蛋白连接的受体和酶连接受体之间G protein-linked receptors bind with an extracellular ligand and activate a membrane protein called a G-protein while enzyme-linked receptors bind with an extracellular ligand and cause enzymatic activity on the intracellular side.

In multicellular organisms, cells communicate with each other via chemical signals. Cells send messages as well as receive messages. Through these messages, all the activities occurring within the organism are coordinated.Paracrine,endocrine,自分泌, and direct signalling are the four major types of cell signalling mechanisms. Cells receive signals through receptors. These receptors can beintracellular receptors或者cell surface receptors. Intracellular receptors are present in the cytoplasm, while cell surface receptors are present on the exterior side of the cell membrane. There are three main types of cell surface receptors as ion channel linked receptors, G protein-linked receptors and enzyme-linked receptors.

内容

1.Overview and Key Difference
2.What are G Protein Linked Receptors
3.What are Enzyme-Linked Receptors
4.Similarities Between G Protein Linked Receptors and Enzyme-Linked Receptors
5.Side by Side Comparison – G Protein Linked Receptors vs Enzyme-Linked Receptors in Tabular Form
6.概括

What are G Protein Linked Receptors?

G蛋白连接受体是一种类型transmembrane proteins. As their name suggests, these receptors work with the G proteins that associate with GTP. GTP is a molecule like ATP that provides energy for G proteins to work. When a ligand binds with the G protein-linked receptor, it undergoes a conformational change in a way that it can interact with the G protein.

The inactive form of the G protein transforms into the active form and divides into two pieces (alpha and beta subunits) by converting GTP into GDP and utilizing the released energy. These subunits then separate from G protein-coupled receptor and interact with other proteins to trigger cell responses. Structurally, G protein-coupled receptors have seven transmembrane domains that span across the membrane.

What are Enzyme-Linked Receptors?

酶联受体是另一种类型的细胞表面受体或跨膜受体。当细胞外配体与酶联受体结合时，这种结合会导致细胞内部的酶促活性。酶激活并启动细胞内的一系列事件，最终导致响应。因此，这些受体具有与酶相关的细胞内结构域。在某些情况下，该细胞内结构域本身起作用，或与酶直接相互作用。在结构上，酶联受体具有较大的细胞外和细胞内结构域和一个跨膜单α-螺旋区域。

Receptor tyrosine kinase is an enzyme-linked receptor. It is a type of receptor protein involved in most of the cell signalling pathways. As its name implies, receptor tyrosine kinases are kinase enzymes. Kinase is an enzyme that catalyzes the transfer of phosphate groups to a substrate. These receptors contain tyrosine kinases that transfer a phosphate group from ATP to tyrosine.

受体酪氨酸激酶具有两个类似的单体。一旦信号分子与受体的结合位点结合，两个单体会汇聚在一起并形成一个二聚体。然后，激酶磷酸化ATP并将磷酸基团添加到六种酪氨酸中的每一个中。因此，二聚体变为磷酸化，这是一种完全活化的酪氨酸激酶。活性酪氨酸激酶将信号发送到细胞的其他分子并介导信号传递。受体酪氨酸激酶的最重要特征是它可以激活多个信号通路，并且当它激活时，它可以一次创建多个细胞反应。

What are the Similarities Between G Protein Linked Receptors and Enzyme-Linked Receptors?

• G protein-linked receptors and enzyme-linked receptors are two categories of cell surface receptors.
• They are transmembrane proteins.
• 它们特定于单个细胞类型。
• Initially, they remain inactive and then become active upon binding a ligand to the receptor.

G蛋白连接的受体和酶连接受体有什么区别？

G protein-linked receptors are the cell surface receptors that activate G proteins upon binding with an extracellular ligand. In contrast, enzyme-linked receptors are the cell surface receptors that activate with an enzyme and sets off a chain of events within the cell. So, this is the key difference between G protein-linked receptors and enzyme-linked receptors. Moreover, G protein-linked receptors have seven transmembrane domains spanning across the membrane while enzyme-linked receptors have a membrane-spanning a single alpha-helical region.

以下信息图提供了更多的比较，该比较将G蛋白连接受体与酶联受体之间的差异相关。

摘要 - G蛋白连接的受体与酶连接受体

G蛋白连接的受体和酶连接受体是两种类型的跨膜受体。G蛋白连接受体与细胞外配体结合，并激活称为G蛋白的膜蛋白。G蛋白激活会触发细胞反应。另一方面，酶联受体与细胞外配体结合并激活酶，该酶触发细胞内的一系列事件，最终导致反应。因此，这些受体的细胞内结构域与酶相关。因此，这是G蛋白连接受体和酶联受体之间差异的摘要。

Reference:

1. “Signaling Molecules and Cellular Receptors.” Lumen,Available here.
2.贵族，戴尔。“受体类型。”神经科学。第二版，美国国家医学图书馆，1970年1月1日，Available here.

Image Courtesy:

1. “G protein” By Tpirojsi – Own work (Public Domain) viaCommons Wikimedia
2.“图09 01 07”CNX OpenStax–(CC BY 4.0)viaCommons Wikimedia