Cell SignallingCell Signalling

Figure source:http://mcb1.ims.abdn.ac.uk/teaching/courses/modules/Ercs.html

Figure source:http://mcb1.ims.abdn.ac.uk/teaching/courses/modules/Ercs.html

Signal transduction refers to how the presence of an extracellular signal can produce a change in the intracellular state of the cell without the initial signal crossing the membrane.

Signal transduction refers to how the presence of an extracellular signal can produce a change in the intracellular state of the cell without the initial signal crossing the membrane.

Signaling is about communication between different groups of cells and tissues…how one group of cells informs another group of cells what to do.

Signaling is about communication between different groups of cells and tissues…how one group of cells informs another group of cells what to do.

Signal transductionsystems

Ca2+/calmodulinadenylate cyclase/cAMPNOPLC/PKCPI/IP3/DAGmembrane receptorsG proteinssteroid hormones

Signal transductionsystems

Ca2+/calmodulinadenylate cyclase/cAMPNOPLC/PKCPI/IP3/DAGmembrane receptorsG proteinssteroid hormones

Cell Signaling Case Study: Secretion of insulin from pancreas cells

Cell Signaling Case Study: Secretion of insulin from pancreas cells

Insulin is secreted in response to elevated blood concentrations of glucose.

Insulin is secreted in response to elevated blood concentrations of glucose.

Glucose metabolism produces cellular ATP,

which closes the ATP-sensitive potassium channel;

then the voltage-dependent L-type Ca2+ channels open.

Ca2+ from the extracellular space (and intercelluar stores) leads to theexocytosis of insulin.

Glucose metabolism produces cellular ATP,

which closes the ATP-sensitive potassium channel;

then the voltage-dependent L-type Ca2+ channels open.

Ca2+ from the extracellular space (and intercelluar stores) leads to theexocytosis of insulin.

How does glucose stimulate insulin secretion from cells of the pancreas?How does glucose stimulate insulin secretion from cells of the pancreas?

Exocytosis Case Study: Secretion of insulin from pancreas cells

Exocytosis Case Study: Secretion of insulin from pancreas cells

In diabetes mellitus, insulin secretion by ß-cells of islets of Langerhans is deficient or absent.

In diabetes mellitus, insulin secretion by ß-cells of islets of Langerhans is deficient or absent.

Cultured Mouse Pancreatic Islets (10x magnification).

Provided by David Zhiyong Gao, Ph.D.

Insulin is a peptide hormone that regulates glucose uptake and metabolism.

Insulin is a peptide hormone that regulates glucose uptake and metabolism.

Mistletoe extract (Viscum album) has a long history as a traditional treatment for diabetes.

Mistletoe extract (Viscum album) has a long history as a traditional treatment for diabetes.

Mistletoe exerts its antidiabetic effect by stimulating insulin secretion.

Mistletoe exerts its antidiabetic effect by stimulating insulin secretion.

Mistletoe extract (Viscum album) has long been used as a traditional treatment for diabetes.

Mistletoe extract (Viscum album) has long been used as a traditional treatment for diabetes.

Mistletoe Exerts Its Antidiabetic Effect by Stimulating Insulin Secretion

Mistletoe Exerts Its Antidiabetic Effect by Stimulating Insulin Secretion

The phospholipase C (PLC)/protein kinase C (PKC) signaltransduction system.

The phospholipase C (PLC)/protein kinase C (PKC) signaltransduction system.

1.Compare and contrast the structures of preproinsulin, proinsulin and insulin. 2.Delineate the sequence of events from transcription of the preproinsulin gene to exocytosis of insulin. 3.List the five steps associated with the synthesis of preproinsulin and its conversion to proinsulin. 4.Describe the mechanisms by which glucose promotes insulin secretion and biosynthesis via ATP closing K+ channels and via diacylglycerol (DAG). 5.Discuss the mechanism by which DAG mediates the ability of muscarinic agonists to promote insulin secretion and biosynthesis. 6.Compare and contrast the effects and mechanism of action of glucagon and epinephrine on insulin secretion.

7.Identify the components of insulin release that are defective in types I and II diabetes mellitus.