Vesicle Transport Chapter 13

Multivesicular bodies form on the pathway to late endosomes

ubiquitin marks protein for destruction

Formation of secretory vesicles

Blood glucose regulation

α and β cells in islet of Langerhans

The Pancreas

Secretory vesicles formed in a insulin secreting β cell of the pancreas stained with clathrin antibody

Release of insulin from a secretory vesicle of a pancreatic β-cell

Insulin signal causes relocation of glucose transporters

Before Insulin Before insulin was discovered in 1921, everyone with type 1 diabetes died within weeks to years of its onset

rapid histamine release by mast cells

Cell Communication chapter 15

Intracellular signaling pathways

4 types of intercellular signaling

Autocrine signaling allow a group of cells but not a single cell to respond to a differentiation signal coordinates decisions by a group of identical cells

Gap junctions allow signaling information to be shared by neighboring cells

figure 05-06b.jpg Gap Junction

An animal cell depends on extracellular signals to survive or divide

An animal cell depends on extracellular signals to differentiate. Without extracellular signals the cell will die

Acetylcholine, a neurotransmitter, can induce various responses in different cells

Chemical Structure of Acetylcholine

Signaling molecules must be turned over rapidly; if turnover time is one minute concentration can decrease rapidly

Signaling molecules must be turned over rapidly; if turnover time is one minute concentration can increase rapidly

Extracellular signaling molecules can bind to intracellular receptors

Acetyl choline causes release of NO which results in rapid relaxation of smooth muscle cells

Signaling molecules that bind to nuclear receptors are small and hydrophobic

Inhibitory proteins make receptor inactive when not bound to the signaling molecule

When signaling molecule binds receptor binds DNA and increases gene transcription

Nuclear receptors have a DNA binding domain

Extracellular signaling molecules can bind to cell surface receptors

3 large classes of cell surface receptors; ion channel linked receptors

Active Chemical Synapse

3 large classes of cell surface receptors; G protein linked receptors

3 large classes of cell surface receptors; enzyme linked receptors