The document discusses the different types of intercellular junctions, including tight junctions, adherens junctions, desmosomes, hemidesmosomes, and gap junctions. It describes the structure and functions of each junction type and how mutations in the proteins that compose the junctions can cause various human diseases. Recent advances include the discovery of tunneling nanotubes that allow direct communication between distant cells.

1. PRESENTOR
Dr. K.AMUDHA LAKSHMI
CO-ORDINATOR
Dr. S. KAVITHA M.D.,
ASSISTANT PROFESSOR

2.  INTRODUCTION
 HISTORY
 CLASSIFICATION
 FUNCTIONS
 APPLIED ASPECTS
 RECENT ADVANCES
 SUMMARY
 REFERENCES

4.  Intercellular connections-cell to cell or cell to ECM.

5.  Tight junction-1963
Marilyn Farquhar
George Palade

6.  Gap Junction-1967
Jean-Paul Revel
Morris karnovsky

7.  Endothelial Tight Junctions from BBB-1967
Thomas Reese
Morris karnovsky

8.  Cadherins -1977
Masatoshi Takeichi
 Desmosomes-1954
K.R.Porter

9.  Tunneling Nanotubes-2004
 A.Rustom
 H.H.Gerdes

10. 1. Tight junction -Zonula occludens.
2. Adherens junction
i. Zonula adherens.
ii. Desmosomes (macula adherens)
iii. Hemidesmosomes.
iv. Focal Adhesions
3. Gap junction - Nexus

13.  Seen between cells in apical margin of
Intestinal epithelial cells ,
Epithelial lining of ducts,
Blood brain barrier,
Blood aqueous barrier,
Renal tubular epithelial cells,
Choroid plexus
 Intercellular space is obliterated.
 Composed of trans membrane proteins:
 Occludin.
 Junctional adhesion molecules (JAM).
 Claudins- (27 genes, claudin-13 absent in humans)
 Linked to Actin filaments

16. FUNCTIONS:
- Strength and stability
- Fencing action
- Maintains the cell polarity
-Blood brain barrier
- Separates apical from basolateral.
- Fascia occludens – present in all blood
vessels (except brain)
- Integral part of vectorial transport or
paracellular transport

18. .
 Seen in
Epidermis,
Columnar lining epithelium,
Heart.
 Adjacent cells – separated by 15-20 nm
 Zonula adherens
 Desmosomes
 Hemidesmosomes
 Focal adhesions

26.  Seen in
Cardiac muscle ,
Smooth muscle,
Embryo blastocyst cells,
Basal part of intestinal epithelium,
Nervous system.
 Inter cellular space 2-4 nm
 Connexon - 6 sub unit protein
 Sub units - connexins

29. FUNCTIONS
i. Intercellular passage of ions, glucose, amino
acids, of molecular weight 1000.
ii. Propagate electrical potential
iii. Exchange chemical messengers
iv. Transfer substances of 2nm size
v. Neuronal gap junctions-periodic synchronized
activity between neurons.

30.  Adhesion Protein molecules-cell to cell , cell to
basal lamina
 Extracellular –to membrane proteins
 Intracellular-to cytosleleton
TYPES
 Cadherins
 Integrins
 IgG superfamily
 Selectins

31.  Binding cells
 Transmit signals
 Inflammation and wound healing
 Metastasis of tumours
 Embryonic development
 Nervous system formation
 Blood brain barrier
 Regulation of apoptosis

32.  Direct communication between T cells
 Connects cell at a distance of up to several cell
diameters
 Tubes with a diameter of 50-200 nm.

33.  Tight junction-Mutation of Claudin gene 16 &
Claudin 19 leads to FHHNC.
 Icthyosis, Sclerolising Cholangitis, Synovial
sarcoma.
 Desmosomes –PKP1 mutation –(plakophillin and
plakoglobin) leads to Skin fragility and
Ectodermal dysplasia, Blistering diseases,
Pemphigus, Keratoderma, Hailey Hailey disease,
Arrhythmogenic right ventricular
dysplasia/cardiomyopathy(plakophillin-2).

34.  Connexin gene mutation – Charcot- Marie-
Tooth diseases, Hereditary deafness(connexin
26 & connexin 30), Cataract, Peripheral
neuropathy, Heterotaxia, Occulodento digital
dysplasia.
 Hemi-desmosomes- Epidermolysis
bullosa(Plectin-PLEC1)

35.  Over the last decade many human gene mutations
have been reported
 Tight junction proteins (claudin 1, 14, 16, and
zona occludens 2),
 Gap junction proteins (connexin 26, 30, 31, 32,
40, 43,46, and 50),
 Adherens junction protein (P-cadherin)

36.  Desmosomes- plakophillin
(PKP) 1 and 2, desmoplakin, plakoglobin ,
desmoglein (DSG)1, 2, 4, and corneodesmosin).

38.  Guyton and Hall- Text Book of Medical
Physiology
 Ganong ‘s Review of Medical Physiology
 Cell Physiology source Book by Nicholas
Sperelakis
 Text book of medical Physiology- Indhu Khurana
 ComprehensiveText Book of Medical Physiology-
G.K. Pal
 Berne & Levy-Text book of Medical Physiology
 Boron-Text book of Medical Physiology