1. Cells communicate with each other through signaling molecules that bind to specific receptors on target cells. 2. Signaling cells produce extracellular signaling molecules that are detected by receptors on target cells, triggering intracellular signaling pathways that elicit responses in the target cells. 3. The same signaling molecule can have different effects on different target cell types depending on the intracellular signaling pathways activated.

1. Komunikasi sel
Dr. Rhandyka Rafli, Sp.OnkRad

2. PRINSIP UMUM
• Sinyal yang disampaikan antar sel berisi informasi sederhana 
ratusan molekul signal (protein, peptide kecil, asam amino acids,
nukleotida, steroids, retinoids, asam lemak, and gas larut)
• sel pemberi sinyal menghasilkan “signal molecule” yang
dideteksi oleh sel target
• Target sel memiliki protein reseptor yang mengenali secara
spesifik dan merespon signal molekul

3. • signal molecule ekstrasel (↓ ↓ ↓ concentrations <10^-8 M)
dan reseptor dengan kemampuan berikatan ↑↑↑ (Ka > 10^8
L/M).
• Umumnya reseptor berupa protein transmembrane pada
permukaan sel target.
• Reseptor + extracellular signal molecule ligand (activated)
 rangkaian sinyal intrasel  respon sel.

4. Sel berkomunikasi menggunakan signal molecule
Hello!
Sel penghasil signaling molecule are disebut signaling cells
Sel penerima sinyal disebut target cells
signaling cell target cell

5. Extracellular signal molecules berikatan pada reseptor spesifik

6. Transduksi sinyal adalah proses dimana bentuk sinyal diubah
menjadi bentuk lain. Target sel dapat mengubah sinyal ekstraselular
(molecule A) menjadi sinyal intraselular (molecule B)

7. signaling pathway intraselular
yang diaktifkan
signal molecule ekstraselular

8. Molekul sinyal yang sama bisa memberikan efek berbeda
pada sel target yang berbeda

9. 4 JENIS
SINYAL
ANTAR SEL

10. Signal molecule
contact
Site of origin Chemical nature Some action
Delta prospectice neurons; various
other embryonic cell types
transmembrane
protein
inhibits neighboring cells
from becoming specialized in
same way as signaling cell
Signal molecule
Paracrine
Site of origin Chemical nature Some action
Signal molecule
synaptic
Site of origin Chemical nature Some action
Acetylcholine nerve terminals derivative of choline excitatory neurotransmitter at
many nerve-muscle synapses
and in central nervous system

11. Signal molecule
Hormone
Site of origin Chemical nature Some action

12. Sinyal ekstraselular dapat mengubah sel target dengan cepat atau lambat

13. Sinyal gas Nitric oksida dapat berikatan langsung pada enzim dalam target cell

14. Reseptor nucleus adalah gen pengatur protein yang diaktivasi oleh ligand
signaling molecules yang berikatan pada reseptor nukleus

15. The nuclear receptor superfamily

16. Aktivasi hormon nukleus reseptor bisa berupa
respon awal primer dan respon lambat secondary

17. 3 kelas utama protein reseptor permukaan

18. Ca2+ berfungsi sebagai messenger intraselular yang luas
Three main types of Ca2+ channels that mediate Ca2+ signaling:
1. Voltage dependent Ca2+ channels in the plasma membrane
2. IP3- (inositol triphospat) gated Ca2+-release channels
3. Ryanodine receptors

19. The concentration of Ca2+ in the cytosol is kept low in resting cells by several
mechanisms

21. Smell and vision depend on GPCRs that regulate cyclic-nucleotide-gated ion channels
Olfactory receptor neurons

22. Signaling through G-protein-coupled cell-surface receptors (GPCRs)
and small intracellular mediators

23. Activation of a G protein by an activated GPCR

24. Some G-proteins regulate the production of cyclic AMP
A nerve cell in culture responding to the neurotransmitter serotonin, which acts through a
GPCR to cause a rapid rise in the intracellular concentration of cyclic AMP

25. Enzyme-coupled cell-surface receptors
1. Receptor tyrosine kinases
2. Tyrosine-kinase-associated receptors
3. Receptor serine/threonine kinases
4. Histidine-kinase-associated receptors
5. Receptor guanylyl cyclases
6. Receptorlike tyrosine phosphatases

26. Some subfamilies of receptor tyrosine kinases
Activated receptor tyrosine kinases (RTKs) phosphorylate themselves