cell signaling mechanism

1. TYPES OF CELL SIGNALING
(with specific example of each)
PRESENTED BY-
NEHA MAYACH
M.Sc. LIFE SCIENCES
(3rd semester)
CENTRAL UNIVERSITY OF GUJARAT
DATE- 11.08.2015

2. CONTENT
• Introduction of cell signaling
• Its need
• Brief history
• Types of cell signaling-
1. Autocrine
2. Paracrine
3. Endocrine
• Recapitulation
• Review article using types of cell signaling
• Reference

3. CELL SIGNALLING- (Brief History)
• In 1970, Martin Rodbell examined effects of glucagon on
rat's liver cell membrane receptor.
• He revealed about guanosine triphosphate and stimulated
G-protein role in cell's metabolism.

5. AUTOCRINE
cells respond to substances which they
themselves release and thus changes takes
place in the cell itself

7. EXAMPLE:-
• Tumour cells
release growth factors for their own survival and proliferation

8. ENDOCRINE
 Signaling over long distance
 Signal molecules(hormones)
secreted by glands
 Bloodstream carries
hormones far and wide may
lie anywhere in the body

10. EXAMPLE:-
Epinephrine-
 amino acid derivative(of tyrosine)
 hydrophilic signaling molecule (bind to G protein coupled receptor)
 Released from Adrenal medulla

11. FUNCTION-
Acts on
LIVER cells
to increase
blood
glucose level
Glycogen
breakdown
Gluconeogenesis
(glucose from pyruvate)

12. Glycogen breakdown Glycolysis(more ATP) Beta Oxidation
(breakdown of fatty
acid for energy)
Acts on MUSCLE cells to make ATP-

13. FIGHT OR FLIGHT
(The physiological response to a threatening situation, which readies
one either to resist forcibly or to run away)
• Muscle needs energy!
• So liver makes glucose and muscle breaks glucose down to ATP.
• Available for use to fight and flight.

14. 7TM receptor(serpentine receptor)
Made up of single polypeptide

16. PARACRINE
Signaling molecules released by a secretory cell affect
only those target cells in close proximity

17. •For paracrine signals to act locally , secreted molecules
must not be allowed to diffuse to far.
•Rapidly taken up by neighboring target cells or
immobilized by ECM.

18. EXAMPLES:-
• conduction by a neurotransmitter of a signal from one nerve
cell to another or from a nerve cell to a muscle cell
• Mostly studies neurotransmitters-

19. NEURO-MUSCULAR JUNCTION

21. Chemically gated receptors or Ion channel receptors

22. ION GATED CHANNEL
Fundamental task of neuron-to
receive, conduct, transmit
signals.
Neurons are excitable cells,
have ability to respond to
stimulus by producing an
electrical signal.
Nerve impulse propagates at
speed ranging from 0.5 to 130
ms.

23. REVIEW ARTICLE
Autocrine insulin-like growth factor-I signaling promotes growth
survival of human acute myeloid leukemia cells via the
phosphoinositide 3-kinase/Akt pathway
• role for autocrine IGF-I signaling in the growth and survival of primary
AML cells.
• IGF-IR inhibitors in combination with chemotherapeutic agents may
represent a novel approach to target human AML(Acute myeloid
leukemia)

24. RECAPITULATE
AUTOCRINE CELL SIGNALING-
normal cell ,cancer cell
ENDOCRINE CELL SIGNALING-
epinephrine, GPCR, G protein, adenylate cyclase, cAMP
fight and flight response
PARACRINE CELL SIGNALING-
Neurotransmitter, neuro-muscular transmitter, ion gated channels

26. REFERENCES:-
I. THE CELL- Geoffrey M.Cooper and Robert E.Hausman (5th edition)
II. BIOCHEMISTRY- Lubert Stryer (6th edition)
III. THE CELL- Alberts (5th edition)
IV. Review(Nature) Leukemia (2007) Nature Publishing Group
www.nature.com/leu

27. THANK YOU