Introduction Definition History Basic element in signal transduction Basic Pathway of signal transduction Types of signal transduction Second messenger Pathway of signal transduction Conclusion References

1. SIGNAL TRANSDUCTION
By
KAUSHAL KUMAR SAHU
Assistant Professor (Ad Hoc)
Department of Biotechnology
Govt. Digvijay Autonomous P. G. College
Raj-Nandgaon ( C. G. )

2. Introduction
Definition
History
Basic element in signal transduction
Basic Pathway of signal transduction
Types of signal transduction
Second messenger
Pathway of signal transduction
Conclusion
References

3. Process of signal transduction involve ordered
sequence of biochemical reaction inside the cell, which
are carried out by enzymes, activates by second
messengers, resulting in a signal transduction pathway.
Cell signaling is a phenomenon in which information is
relayed across the plasma membrane to the cell interior
and often transmitted to the cell nucleus.

4. Signal transduction is a series of steps by which
external stimuli are converted into chemical signals
and then into cellular responses.
A hormone bind to a specific receptor in plasma
membrane. This stimulates the cell to produce
second messenger which relay the hormonal signal to
intracellular sites triggering(as a fire arm) the cells
various responses to the original signal.

5. In 1970 Martin Rod bell Firstly examined Signal
Transduction, through effect of glucagons on a rat’s
liver cell.
glucagons
+ bind
Guano sine triphosphate disassociated
glucagons
↓
stimulates G- protein
↓
strongly influences the cell metabolism

6. 1- Ligand – An extra cellular molecule whether
organic or inorganic which binds to receptor and
there by alter its function is called ligand. E.g.
ions, sugars, proteins. Also known as signals or
first messenger.
2- Receptor :-
Trans membrane protein that binds to the
ligand. Receptor for secreted molecules
(including protein, small peptides, amino acids,
etc)

7. 3- Second messenger-
second messenger, molecule inside cells that acts
to transmit signals from a receptor to a target.

8. Autocrine
Autocrine signaling is a form of cell signaling in
which a cell secretes a hormone or chemical
messenger (called the autocrine agent)
That binds to autocrine receptors on that same
cell, leading to changes in the cell.

9. Paracrine
Paracrine signaling is a form of cell signaling in
which the target cell is near ("para" = near) the
signal-releasing cell.

10. Endocrine
when cells need to communicate a message over a
long distance, they can use the endocrine system.
Endocrine signalling uses chemicals called
hormones to send messages throughout the body.
E N D OCR I N E SI GN A LI N G

11. A-Reception: A cell detects a signaling molecule from
the outside of the cell. A signal is detected when the
chemical signal (also known as a ligand) binds to a
receptor protein on the surface of the cell or inside the
cell.
B:Transduction: When the signaling molecule binds
the receptor it changes the receptor protein in some
way. This change initiates the process of transduction.
C-Response: Finally, the signal triggers a specific
cellular response.In the third stage of cell signaling,
the transduction processes brings about a cellular
response to the stimulus.

13. Extra cellular Signal Transduction
Inter cellular Signal Transduction
Intra cellular Signal Transduction

14.  Extra cellular signals are those come from out
of the network and that gives some effect to the
network via specific interaction with one of the
molecules in the network.
 Most extra cellular chemical signals are water
soluble and membrane impermeable. Example
– Steroid hormones.

15. This type of signal transduction describes the mechanism by
which one cell (sender cell) send a message to change the
function of another cell (target cell).
Two cells can communicate by two methods –
Contact dependent signaling – This type of signaling
requires direct physical contacts between sender cell
and target cell.
The second method involved release of secreted
molecules from the sender cell to the target cell and
does not requires direct contact between the sender
cell and target cell .

16. Intra cellular signal transduction is largely carried
out by second messenger molecules .
Intracellular signaling molecules in
eukaryotic cell includes. heterotrimeric G-
protein small GTPase, cyclic nucleotide , such
as cAMP , cGMP and Ca2+ ion.

22. In vertebrate eye , it responsponsible for converting the
visual signals received as light to nerve impulses.
The photoreceptor in rod cells of the retina is a G
protein-coupled receptor called rhodopsin.

24. Inositol trisphosphate or inositol, IP3 binds to and activates
the InsP3 receptor on the membrane of the endoplasmic
reticulum (ER)opens a calcium channel, resulting in the
release of Ca2+ into the cytoplasm.
Calcium ions (Ca2+) and inositol trisphosphate (IP3) function
as second messengers in many signal transduction pathways.

26. Calcium (Inactive state)
↓
First messenger comes and binds to receptor
↓
This interaction induces a conformational change in
proteins
↓
Protein specific to calcium channels open the channels
for Ca
↓
Calcium ions exit from intracellular storage sites into the
cytoplasm
↓
Calcium (active state)
↓
Carries message to the target site
↓
Triggers target site for response
FUNCTION: Muscle contraction, vision in retina cells,
proliferation of cells

27. Gated ion channels
Cyclic nucleotide-gated ion channels
Their function can be the result of a combination of the
binding of cyclic nucleotides (cGMP and cAMP) and either a
depolarization or a hyperpolarization event.
Initially discovered in the cells that make up the retina of the
eye, CNG channels have been found in many different cell
types across both the animal and the plant kingdoms.

29. Binding of insulin of the α chain activates the tyrosin
kinase activity of β chain and each α- β monomer
phosphorylase 3 criticle tyrosin residuce near the
terminal of β chain.

31. .
 Many extra cellular stimuli (first messengers) initiate
responses by interacting with G- protein coupled
receptors (GPCR) on the outer cell surface and
stimulating the release of a second messenger within
the cell.
 The signal is transmitted from the receptor to the
effector by a heterotrimeric G- protein.
 These proteins are referred to as heterotrimeric because
they have three subunits (α, β and γ) and as G proteins
because they bind guanines either GDP or GTP.

33.  Finally we conclude that signal transduction is a
universal property of living cells, which is found in
plant cell, wells as in unicellular cells.
 Animal cell exchange information about the
concentration of ion and glucose in extracellular.

34. THE CELL- A Molecular Approach- By M.Cooper & Robert E.
Hausman (5th Edition)S
Text Book of cell Biology- By Karp
Genetics- By B.D. Singh
Website
www.wikipedia.org/(8.45 pm)