Cell to cell Cell to cell signalingsignaling

Mayank AgarwalMayank AgarwalShiv Shiv

IshpujaniIshpujani

What is cell signaling?What is cell signaling?A form of communication

Cells use chemical messengers (special signalling molecules) to communicate with each other

Cell to cell signaling allows organisms to coordinate the activity of a wide variety of different cell types

Why?Why?

How?How?

Steps Steps

Extracellular signaling molecule transmission

Binds to its receptor transduction

Production of 2nd messengers or

alteration in ionic channels

Effect

Receptor typesReceptor types

Cell surface receptors

Mechanism ExamplesOpen/close the ion channels in cell membranes

A.Ch. on nicotinic cholinergic receptor

Increase the transcription of certain mRNAs

Thyroid hormone, retinoic acid, steroid hormone

IP3 mechanism Angiotensin II, nor epinephrine

Increase cGMP ANF, NOIncrease tyrosine kinase activity Insulin

Increase serine or threonine kinase activity Inhibin

TransductionTransduction

CaCa2+2+ as second messenger as second messenger

Helps in many physiological roles such as fertilisation, neural signaling, contraction etc.

IPIP33 and DAG pathway and DAG pathway

PIP2 = Phosphatidyl inositol 4,5- bisphosphate; IP3 = Inositol Triphosphate; DAG= Diacyl Glycerol

cAMP/ Adenyl CyclasecAMP/ Adenyl Cyclase

Target tissue Hormone Major response

Thyroid gland Thyroid-stimulating hormone (TSH)

Thyroid hormone synthesisand secretion

Adrenal cortex Adrenocorticotrophic hormone (ACTH) Cortisol secretion

Ovary Luteinizing hormone (LH) Progesterone secretionMuscle Adrenaline Glycogen breakdownBone Parathormone Bone resorption

Heart Adrenaline Increase in heart rate andforce of contraction

Liver Glucagon Glycogen breakdownKidney Vasopressin Water resorption

Fat Adrenaline, ACTH, glucagon, TSH Triglyceride breakdown

Some Hormone-induced Cell Responses Mediated by Cyclic Some Hormone-induced Cell Responses Mediated by Cyclic AMPAMP

cGMP pathwaycGMP pathway

GC: guanylyl cyclase PDE: phosho-diesterasePKG: protein kinase G

Bibliography Bibliography ◦Hall JE. Guyton and Hall text book of medical physiology. 13

ed. USA: Elsevier; 2016.

◦ Barret KE, Boitano S, Barman SM, Brooks HL. Ganong’s review of medical physiology. 25 ed. New Delhi: Tata McGraw-Hill; 2016.

◦ Alberts B, Johnson A, Lewis J, Morgan D, Raff M, Roberts K et al. Molecular biology of the cell. 6 ed. USA: Garland Science; 2015

◦ Koeppen BM, Stanton BA. Berne & Levy physiology. 6 ed. Canada: Elsevier; 2010.

◦ Chandar N, Viselli S. Lippincott’s illustrated reviews: cell and molecular biology. 1 ed. China: Wolter Kluwer; 2010.

Incoordination will Incoordination will result due to defect result due to defect

in cell signalingin cell signaling

Thank youThank you