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Cell signaling an over view
- 1. UNIT4-CELL COMMUNICATION & CELLSIGNALLING CELL SIGNALLING –AN OVERVIEW
- 2. INTRODUCTION: Synthesis & releaseof signalling molecule by the signalling cell & its transport to target cell Binding of the signal by a specific receptor leading to its activation Initiation of signal transduction pathway.
- 5. Types of signalingmolecule- 1)MEMBRANE BOUND SIGNAL MOLECULE –bound to membrane,contact dependent signaling 2) SECRETORY SIGNAL MOLECULE –Signal molecules secreted by signaling cells. Fall in to two categories: • Small lipophilic molecules that cross membrane & interact with intercellular receptors. • Hydrophilic molecules that binds with cell surface receptors.
- 6. Examples of signaling molecules extracellular Epinephrine,nonep inephrine,insulin, gastrin Secritin, Cholcystokinin& ACTH intracellular STERIOD – Progestrone,estradiol,Test osterone,cortisol,aldoster one Non steroid- Thyroid ,retinoic acid
- 7. Receptors : Bindingof signaling molecule to the receptor causes a conformational change in the receptor ,which initiates a sequence of events leading to a specific cellular response. They are usually made up of glyco proteins Signaling molecules are also called LIGANDS. Two types based on their location: 1. Intracellular receptor(nuclear/cytosolic)
- 10. Cell surface receptors/extracellular receptors- Hydrophilic signaling molecules & few lipophilic signaling molecules bind to cell surface receptors. Binding of ligands causes conformational changes in receptors ,producing intracellular messengers which stimulates effectors activating cellular responses
- 11. Types of cellsurface receptors G protein coupled receptor Ion channel receptor Enzyme linked receptors
- 12.