Multicellular organisms need to communicate:

1. Within the cell 2. To cells nearby 3. With cells far away

Communication is universal and important for medicine:

1. Embryology and development 2. Cancer and disease

What binds to the receptor protein?

signal molecule (ligand)

The ligand can be?

1. Hormone 2. Neurotransmitter 3. Growth Factor

What is a hormone?

chemical released by an endocrine organ

3 different types of hormones:

1. Peptide hormone, ex: insulin 2. Amine hormone, ex: epinephrine 3. Protein hormone, ex: Follicle-stimulating hormone

What is a neurotransmitter:

a chemical released by a neuron that binds a receptor at the synaptic cleft or motor end plate

What is a growth factor?

a chemical messenger acting locally to cause cell growth, proliferation, or cell differentiation. Is usually a protein or steroid hormone

Steroid hormones:

1. can be classified by the 5 receptors to which they bind 2. Readily diffuse across the cell membrane because hydrophobic; bind to receptors inside the nucleus that modulate expression of genes.

5 different types of steroid hormones:

1. Glucocorticoid- turns inflammation down, ex: cortisol 2. Mineralocorticoid- characterized by influence on salt and water balance, ex: aldosterone 3. Androgens- stimulate or control the development of male sex characteristics, and the precursor for all estrogens, ex: testosterone 4. Estrogens- primary female sex hormone, ex: estradiol 5. Progestogens- important for maintaining pregnancy, ex: progesterone

What is autocrine?

a cell secretes a chemical messenger that binds a receptor on its own surface

What is Paracrine?

a cell secretes a chemical messenger that binds a receptor on an adjacent or neighboring cell.

What is endocrine?

a cell secretes a chemical messenger into the blood that binds a receptor on a distance target.

What is a kinase?

Enzymes that add phosphate groups

Protein Kinase A (PKA):

Allosteric activator is cAMP

Protein Kinase C (PKC):

Allosteric activator is DAG

MAP Kinase (MapK):

activated by Ras* (Ras is activated by exchanging a GDP for a GTP)

What are Phosphatase?

enzymes that take away phosphate groups, DEPHOSPHORYLATE

What is a Phosphorylation Cascade?

When a bunch of kinase enzymes are in a row and activate the next kinase.

Important Phosphorylation cascade to know:

1. MAPKKK (MAP kinase kinase kinase) activates MAPKK (Map kinase kinase) 2. MAPKK activates MK (MAP Kinase) 3. Map Kinase activates a response protein 4. *This phosphorylation cascade is mediated by a scaffold protein

What is a scaffolding protein?

These are proteins that hold the enzymes that will be used in a series in the cell. Keeps reactions organized.