Biology Forum › Cell Biology › Phagocytosis
November 15, 2005 at 4:51 am #2515
What is the difference between phagocytosis and receptor mediated phagocytosis?
November 15, 2005 at 5:07 am #32724
Receptor mediated endocytosis is a process by which cells internalize molecules or viruses. As its name implies, it depends on the interaction of that molecule with a specific binding protein in the cell membrane called a receptor. Normally the receptor is clathrin coated pits.these receptors are absent in normal phagocytosis. Phagocytosis (“cell eating”):
results in the ingestion of particulate matter (e.g., bacteria) from the ECF.
The endosome is so large that it is called a phagosome or vacuole.
Phagocytosis occurs only in certain specialized cells (e.g., neutrophils, macrophages, the amoeba), and
Some of the integral membrane proteins that a cell displays at its surface are receptors for particular components of the ECF. For example, iron is transported in the blood complexed to a protein called transferrin. Cells have receptors for transferrin on their surface. When these receptors encounter a molecule of transferrin, they bind tightly to it. The complex of transferrin and its receptor is then engulfed by endocytosis. Ultimately, the iron is released into the cytosol.clathrin occurs as triskelion.
November 15, 2005 at 9:26 pm #32819
lara is right. but i am curious about your question that mentiones “receptor mediated phagocytosis” and not receptor mediated endocytosis(which is probably what the teacher wanted). although none of my books say anything about receptor mediated phagocytosis the amoeba can make a difference between food and non-food. How is that done?
November 16, 2005 at 7:56 am #32854
The process by which a cell engulfs material to bring it into the cell is called endocytosis. Two major forms of endocytosis are:
Phagocytosis refers to the process of engulfing large particles.
so, if large particles are taken in with the help of receptors can v call it rreceptor mediated phagocytosis??
November 16, 2005 at 7:25 pm #32904
That is what you will find in a 30 year-old book(that phagocytosis and pinocytosis are types of endocytosis). the currect opion restricts phagocytosis to taking large particles or whole cells from the environment by creating cellular extensions by using polimerisation of actin molecules
November 17, 2005 at 1:12 am #32935
You guys are pretty hardcore.
I would expect in order for the cell to engulf the particle, the cell needs to know the particle is around in the first place. The only way it knows that is to have the particle bind with a certain receptor.
Unless, you are telling me that the cell engulf the large particle without any receptor, and the particle they are engulf is non specific for normal phagocytosis….
November 17, 2005 at 7:52 am #32959
seems u forgot to read in your 30-year old textbook that receptor mediated phagocytosis(not endocytosis too occur in bacteriaI”would expect in order for the cell to engulf the particle, the cell needs to know the particle is around in the first place. The only way it knows that is to have the particle bind with a certain receptor” xactly!!
November 17, 2005 at 7:35 pm #32995
Yeah, but is that part of phagocytosis? And if it is, what is non-receptor mediated phagocytosis?
November 18, 2005 at 9:06 am #33022
So what is the difference then? They both need receptor don’t they?
I don’t recall I have a 30 years old textbook hehe
November 18, 2005 at 12:01 pm #33033
It is “receptor mediated endocytosis”. In receptor mediated endocytosis the material should be specific. Means not all of the cells can get everything. An extracellular material called ligand is links to the receptor, forms a ligand-receptor complex. (examples of ligands: LDL, transferrin) The vesicle is covered with a protein membrane-like structure. Then taken into the cytosol. Then carried to the lysosome.
November 18, 2005 at 7:16 pm #33057
Yeah, we all know that ozge. the formation of a clatrin coatet vesicle. but what about phagosytosis? Can there be receptor mediated phagocytosis and non-receptor mediated phagocytosis?
November 20, 2005 at 5:15 pm #33122
I tried to say that I haven’t heard about it.
November 21, 2005 at 1:03 am #33152
Yup Yup. I know that they are taken in and fused with lysosome ….
so what is the difference between phagocytosis and receptor mediated phagocytosis.
My text book said, there are three types of endocytosis: pinocytosis, phagocytosis, and receptor mediated phagocytosis. And the definiteion it gives for phagocytosis and receptor mediated phaogcytosis are nearly identitcal.
November 21, 2005 at 9:05 pm #33192
It is not receptor mediated “phagocytosis” (at least in my book), It is receptor mediated “endocytosis”.
For your question about the difference, blackmangoes, read my previous post. I tried to explain the difference. 🙂
November 23, 2005 at 7:48 am #33303
For those that care about this question. Here is the answer
This figure diagrams the major internalization events. In the two views on the right, receptors are not needed for internalization. During phagocytosis, cells may simply internalize particles or cells, like bacteria (cell eating). In the second, called pinocytosis, cells internalize soluble material (cell drinking). In both types of internalization, the cells extend processes and bring cells or soluble material into the cell in a vacuole. In the presentation on lysosomes , we learned that the vacuole formed in the cell by phagocytosis or pinocytosis often became a lysosome after hydrolases were brought to it and the pH was adjusted. The vacuoles formed are called phagosomes or macropinosomes. This cartoon was taken from Endocytosis, Edited by Ira Pastan and Mark C. Willingham, Plenum Press, N.Y., 1985
Endosomes are formed by receptor-mediated endocytosis. In this case, cells bring in proteins and other types of ligands attached to the plasma membrane via receptors. The process depends first on specific binding to the receptor, which is a subject worthy of a lecture in itself. This figure shows this process as “coated pit endocytosis”. The coated pit is a specialized region of the membrane that is coated with clathrin (for stability, to aid the transport process). The coated pit forms a coated vesicle and then loses its clathrin coat. It then joins with other coated pits to form a receptosome.
taken from http://cellbio.utmb.edu/cellbio/recend.htm
November 24, 2005 at 12:59 am #33377burningredphoenixParticipant
Easy, receptor mediated designates certain molecules ; phagocytosis does not
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