July 18, 2019 Thursday
Bedtime Story
G Protein-Coupled Receptor in Immune System
Olfaction plays a key role in organism’s
quest for meals and mate and at the same time is the first sense to send alarm
bells ringing in the presence of an attack from a predator or natural disasters
(think of forest fires or volcano eruption or even a meteorite hitting the
planet).
(d) Regulation of immune system and role in
inflammation: the receptors of chemokines are G Protein-Coupled Receptors.
Chemokine I understand should be a new word
for most of you even if you are a medical student and more so if you are a
practicing doctor since then your entire life is dedicated towards increasing
your patient flow and thereby your cash kitty.
Understandably then non-medicos and
biologists should be pardoned for their ignorance and since they can be
pardoned then the general population gets a free ride of forgiveness from the
story-telling chimpanzee.
Chemokines are a type of cytokines which in
turn are special type of small proteins that are secreted by specialized cells
that send signals to other cells.
Cytokines are such small proteins that the
correct term for them is peptide and being a peptide they are not able to enter
or cross the bi-lipid layer of cell membranes into the cytoplasm.
Hence they only way they can affect
behavior of other cells is through the means of G Protein-Coupled receptors.
Cytokines largely play a role in the
humoral and cellular immunity of organisms in very complex ways that I cannot
go into at present but who knows some night I will.
Chemokine is a portmanteau word (but not a
contraction) constructed out of “chemotactic” and “cytokine”.
They have been aptly so named because they
have the ability to induce specifically directed chemotactic activity on cells.
Chemotaxis (taxis is Ancient Greek for ‘arrangement’)
refers to movement of cells or cellular organisms in response to chemical
stimulus.
Chemokines therefore are the agents that
scream out loud when they encounter breach in the immune system or come across
invaders in the system.
Their signaling brings in and recruits
several type of inflammatory cells at the specific site leading to the five
clinical signs of inflammation – calor (heat), dolor (pain), rubor (redness),
tumor (swelling) and functio laesa (loss of function).
When you suffer an injury or when you are
invaded by viruses in your nose or upper respiratory tract (which is far more
common that we would like it to be) or bacteria in the urinary tract (more
common in women than men due to their shorter urethra to urinary bladder) and it is these peptides call chemokines that
bring in the army of inflammatory cells to the site of attack.
The message to the inflammatory cells by
the chemokines and their response to it is affected through these magical
molecular switches on the surface of inflammatory cells such as leucocytes,
monocytes/macrophages, T-lymphocytes, mast cells and eosinophils.
Stay tuned to the voice of an
average story storytelling chimpanzee or login at http://panarrans.blogspot.com
Good night Mon Ami and my fellow cousin ape.
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Another great educator and a teacher that I am aware of is
Professor Subhashish Chattopadhyay in Bangalore, India.
While I narrate stories, Professor Subhashish an electronic
engineer and a former professor at BARC, does and teaches real mathematics and
physics.
He started the participation of Indian students at the
International Physics Olympiad.
Do visit him here:
All his books can be downloaded for free through this link:
For edutainment and English education of your children, I
recommend this large collection of Halloween Songs for Kids:
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