Question

Explain the Cell Signaling Analysis.

Answer 1

CELL SIGNALING:

IT IS A PART OF COMMUNICATION PROCESS THAT GOVERNS ACTIVITIES OF CELLS AND CO-ORDINATE MULTIPLE CELL ACTIONS.

IMPORTANCE::

1.Helps in basis of tissue development ,tissue repair, immunity as well as normal tissue homeostasis

2.Errors in this causes diseases like CANCER, AUTO IMMUNITY AND DIABETES

3.Cell signaling helps clinicians to treat diseases more effectively and theoretically

4.researchers may develop new tissues

All cells receive and respond to signal from surrounding.This is accomplished by a variety of signal molecules that are secreted or expressed on the surface of one cell and bind to receptors expressed by other cells there by integrating and coordinating the function of many individual cells that make up an organism

This is usually studied between cells of single organism but it may occur between cells of different organism

example:early embryo cells exchange signals with cells of uterus

STEPS :

1.SYNTHESIS AND RELEASE OF SIGNALING MOLECULE BY THE SIGNALING CELL

2.TRANSPORT OF SIGNAL TO THE TARGET CELLS

3.BINDING OF SIGNAL BY SPECIFIC RECEPTOR LEADING TO ITS ACTIVATION

4.INITIATION OF SIGNAL TRANSDUCTION PATHWAY

CLASSIFICATION :

BASED ON TYPE OF SIGNAL

1.MECHANICAL----these are the Forces exerted on the cell and forces produced by the cells.these can be sensed and responded to and by the cells

2.BIOCHEMICAL------These signals are the biochemical molecules such as proteins,lipids ,ions and gases

SIGNALS ARE CATEGORIZED BASED ON DISTANCE BETWEEN SIGNALING AND RESPONDING CELLS

SUB TYPES

1. INTRACRINE----Signals are produced by target cell that stay with in them
2. AUTOCRINE----Signals are produced by target cell,they affect themselves or the adjacent cell if they are of same type
3. example--immune cells
4. JUXTACRINE---Signals target the adjacent cells which are in touch and transmit signals along cell membrane through protein or lipid components-----DIRECT COMMUNICATION
5. PARACRINE---Signals target cells in vicinity of emitting cell ex: neurotransmitters-----SHORT DISTANCE COMMUNICATION
6. ENDOCRINE--Signals target distant cells for example hormones which travel through blood to reach all body parts---LARGE DISTANCE COMMUNICATION   

CELL SIGNALING PROCESS   

cells have proteins called RECEPTORS ( these are trans membrane proteins and are very specific) that bind to signaling molecules and initiate a physiological response.for example dopamine receptors bind dopamine

---Then the receptors transmit the signal through a sequence of molecular switches to internal signaling pathways

--INTRA CELLULAR SIGNALING PATHWAYS ALSO CALLED SIGNAL TRANSDUCTION CASCADES

--They amplify the message and produce multiple intra cellular signals for every receptor that is bound

--activation of receptors can trigger synthesis of small molecules called SECOND MESSENGERS which help in initiating and coordinating the process

--Protein kinase catalyzes the transfer of phosphate groups from ATP molecules to protein molecules

-this phosphorylation reactions control the activity of many enzymes which are involved in intra cellular signaling pathways ...conformational changes are seen in enzymes which can either activate or inhibit the enzyme activity

---protein phosphatases remove phosphate group from enzymes there by reversing the enzyme activity

EXAMPLE:

(a) The general flow of information during cell signaling Ligand (primary messenger) Receptor CYTOSOL Receptor-ligand binding 3 Cellular responses NUCLEUS 2 Signal transduction (via second messengers) wa 4 Changes in gene expression (b) Different ways in which signals can be integrated Pathway Pathway #1 #2 Single pathway Pathway Pathway #1 #2 1 One receptor 2 Different receptors 3 Different receptors activates multiple activate the same activate different pathways pathway pathways; one pathway affects the other © 2012 Pearson Education, Inc.

At one time cell receives and responds to numerous signals and MULTIPLE SIGNAL TRANSDUCTION pathways operate in its cytoplasm.many points of intersection exist among these pathways

Through this network of signaling pathways,the cell is constantly integrating all the information it receives from its external environment.