Gap junction by subhrajyoti sahoo

It is about the Gap junction.

1. G a p j u n c t ion a n d c o n n e x i u s B y s u b h rajyoti sahoo

2. introduction specialised junction are found in all animals tissue among cells of tissue between c e l ls and is E CM to allow for cell cell and cell matrix contacts . Cell junction also found in plants and describe their is plasm a desmata . There is t hree type of cell junction first one is o c c u l a d i n g junction next anchoring junction and last one is communicating junction . The gap junction is included in the communicating junction

3. D e f i nition G a p junction ar e type of cell junction in which adjacent cell are connected through protein channels . in cell cell attachments and communication are also facilitated by c e r t a i n proteins and which is 2 n m to 4 n m wide gap is known as gap junction .

4. History In 1953 first time the Gap j u n ction is shown by the transmission electrons microscope ( T E M ) . The term g ap junction appeared to be coined about 16 years later " c i r c a " 1969 from the 1953 first scene .

5. Structure of GAP junction Structurally g a p junction consists of all channels found which series of 6 p r o t e i ns s u b u n i ts a r e l o c a ted . The channel diameter is about 1.5 to 2 n m . it forms intracellular pipes through which exchange certain substance between two adjacent cell takes place . G a p j u n c t ion on channels formed from two identical Hem i channels are called home t y p i c while those with different channels are heterotypic .

6. G r o u p s o f s i x c o n n e x i n s f r o m a c o n n e x o n , a n d t w o c o n n e x o n s a r e p u t t o g e ther t o f o r m a c h a n n e l s t h a t m o l e c u l e s c a n p a s s t h r o u gh H u n d r ed o f c h a n n els a r e f o u n d t o g e t her a t t h e s i t e o f gap ju n c tion i n w h a t i s k n o w n a s g a p j u n c tion p l a q u e .

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9. Working mechanism of GAP junction Amp and ca + + can also pass through gap junction to allow propagation of response to e x t r a c ellular signals . the channels formed by ge p j u n c t ion do not allowed remain open and that the opening of the po r e is regulated by changes in pH and calcium + + ion concentration . For this cause became g a p junction a dynamic in structure like ion channels . During embryogenesis cells are electrical component due to pass of iron t h r o u gh g a p junction

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11. Functions of GAP junction The skeletal muscle cells and blood cells in animal tissue are in communication with their neighbour v i a gap junction . it is responsible for the transmission of signal required for the drugs to heav an effect and conv e r s e l y s o m e d r u g s were shown to block gap junction channels . In the brain they are concentrated in the cerebellum which is involved in coordinating rapid nuclear activities . In the h e a r t tissue for example gap junction facilitated the flow of electrical current that causes the heart to beat .

12. About c o n n e x i u s One connexin protein has four transmembrane dominance . 6 con n e x i n s create one conne x o n . when different con n e x i n s in join together to form one con n e x o n it is called a heteromeric connection . when two identical conn e x o n s come together to form a gap junction channel it is called ho m o t y p i c gap junction channel . when a con n exons comes in contact with a similar channels form and adjoining cell it forms a gap junction providing communication between cytoplasm of the two cells

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