Komunikasi Sel_biosel Reg 23_24.pptx.pdf

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1. CELLULAR
COMMUNICATION

2. Signalling pathway of glucose intake
www.youtube.com/watch?v=JAjZv41iUJU

4. The Cellular “Phone”
In multicellular organisms, cells constantly send and receive chemical messages to coordinate
the actions of other organs, tissues, and cells. The ability to send messages quickly and
efficiently enables cells to coordinate and fine-tune their functions.

In order to properly respond to external stimuli, cells have developed complex mechanisms of
communication.

Cells can receive a message, transfer the information across the plasma membrane, and then
produce changes within the cell in response to the message, commonly called “signal
transduction pathway”


INTRODUCTION

5. Signal transduction pathway is a series of steps by which a
signal on a cell’s surface is converted into a specific cellular
response

The ability of cells to perceive and correctly respond to their
microenvironment is the basis of development, tissue repair,
and immunity, as well as normal tissue homeostasis.

Errors in signaling interactions and cellular information processing
are responsible for diseases such as cancer, autoimmunity, and
diabetes.

INTRODUCTION

6. Signal transduction pathways convert signals on a cell’s
surface into cellular responses
INTRODUCTION
Not all cells can “hear” a particular chemical message. In order to detect a signal (that is,
to be a target cell), a neighbor cell must have the right receptor for that signal.

7. Cell Signaling PURPOSE
PROTEIN
PRODUCTION

8. IMMUNE SYSTEM ACTIVATION
By The cytokines : Monokines, Interleukins, Interferon

▪Macrophages release monokines. Some monokines
attract neutrophils to the macrophages.
▪Some monokines cause B cells to differentiate and
release antibodies.
Cell Signaling PURPOSE

9. IMMUNE SYSTEM ACTIVATION
By The cytokines : Monokines,
Interleukins, Interferon

▪T cells and macrophage release
interleukins. The cytokine
interleukin stimulates proliferation
(a rapid rush of cell division by
mitosis, over and over again) of B
and T cells.
▪This produces thousands of
identical B and T cells and is
called clonal expansion. The T
and B cells then differentiate
Cell Signaling PURPOSE

10. Cell Signaling PURPOSE

11. Cell Signaling PURPOSE

12. Types of Chemical
Signaling
▪ Chemical signaling
between cells is one of
the most important ways
that activities of tissues
and organs are
.coordinated
▪ The nervous system is the
other major
coordinating system in
animals, but even here
chemical signaling is
used between adjacent
.neurons

13. Modes of cell-cell signaling
1.Direct cell-cell or cell-matrix

2.Indirect: Secreted molecules.

A.Autocrine signaling
B.Paracrine signaling
C.Endocrine signaling
SIGNALING TYPE

14. •Cells in a multicellular
organisms communicate by
chemical messengers
•In local signaling, cells may
communicate by direct
contact
DIRECT SIGNALING: Local and Long-Distance Signaling

15. DIRECT SIGNALING: Local and Long-Distance Signaling
•Humancells have cell
junctions that directly
connect the cytoplasm of
adjacent cells
•Direct signaling between
immune cells

16. A.Endocrine signaling. The
signaling molecules are
hormones secreted by
endocrine cells and carried
through the circulation system
to act on target cells at distant
body sites.

B.Paracrine signaling. The
signaling molecules released by
one cell act on neighboring
target cells (neurotransmitters)
C.Autocrine signaling. Cells
respond to signaling molecules
that they themselves produce
(response of the immune system
to foreign antigens, and cancer
cells).

INDIRECT SIGNALING: SECRETED MOLECULES
A
C
B

17. •Cells in a multicellular organisms
communicate by chemical
messengers
•In long-distance signaling, plants
and animals use chemicals called
hormones
INDIRECT SIGNALING: exp. Endocrine Signaling
Hormone
travels
in
bloodstream
to target cells

18. 1. Steroid hormones
▪This class of molecules diffuse
across the plasma membrane
and bind to Receptors in the
cytoplasm or nucleus. They are
all synthesized from cholesterol.
▪EXAMPLE: The hormone-receptor
complex enters the nucleus and
binds to specific genes where it
acts as a transcription factor
which turns on the genes.

Example of Some Signaling Molecules

19. 2. Nitric oxide (NO)
NO, a simple gas, is able to diffuse across the membrane, and alters the activity
of intracellular target enzymes. It’s extremely unstable, so its effects are local.
Ex. It signals the dilation of blood vessels.
Example of Some Signaling Molecules

20. 3. Neurotransmitters:
The signal from neuron to
neuron or from neuron to
other target cell
(ex. muscle cell ).

Example of Some Signaling Molecules

21. ▪Earl W. Sutherland discovered how the hormone epinephrine/adrenaline acts
on cells
▪Sutherland suggested that cells receiving signals went through three
processes: 1) Reception2) Transduction3) Response
Three Steps in Cell Signaling

22. 1. Reception : A signal molecule binds to a
receptor protein, causing it to change shape
•The binding between a signal
molecule (ligand) and receptor is
highly specific
•A conformational change in a
receptor is often the initial
transduction of the signal
•Most signal receptors are plasma
membrane proteins.
•Ex : G-Protein-linked Receptor
Three Steps in Cell Signaling

23. 1. Reception
•Ex : G-Protein-linked
Receptor.
•Receptor tyrosine
kinases are
membrane receptors
that attach
phosphates to
tyrosines
Three Steps in Cell Signaling

24. 2. Transduction and
Response: Cascades
of molecular
interactions relay
signals from receptors
to target molecules in
the cell
Three Steps in Cell Signaling

25. The Cellular “Phone” by
INTRODUCTION
Chemical signal or ligands