BIOL 3090 study guide Chapter 20

Chapter 20

20.1 Extracellular signaling

Endocrine, paracrine and autocrine signaling (Figure 20.1

Know the six steps of signaling

Definition of ligand, growth factors and cytokines

Types of ligands

1. small lipophilic ligands with internal receptors

2. Water soluble ligands with cell surface receptors

3. lipophilic ligands with cell surface receptors

Figures 20-2*

Classes of cell surface receptors

1. intracellular receptors

2. cell surface receptors (Figure  20-3*) (very important)

a. G-protein linked receptors

b. ion channel receptors

c. tyrosine kinases-linked receptors

d. receptors with intrinsic activity

Second messengers (Ca²⁺, cAMP, IP₃, DAG) Figure 20.4

GTPase switch protein and adapter proteins (Figure 20.5)

20.2 Identification and Purification of Receptors

Figure 20-7, 20-8 and 20-9)

20.3  G-protein coupled receptors

General structure Figure 20-10

How the G-protein activates adenylate cyclase (Figure 20-16)

Multiple receptors can change adenylate cyclase activity (Figure 20-18)

Cholera toxin (Figure 20-17)

20.4 Receptor tyrosine kinases and Ras

General structure of RTKs (Figure 20-21)

Ras, GEF and GAP (Figure 20-22)

Activation of Ras with GRB2 and Sos (Figure 20-23) Very important

What is an SH2 and SH3 domain?

20.5 MAP kinase pathways

Protein kinase cascade Ras to Raf to MEK and MAPKinase (Figure 20-28) – very important

Ras is mutated in many types of cancers

20.6  second messengers

Glycogen regulation - Figures 20-34, 20-35***, 20-36

Also make sure to look over the text I gave you in class on this material

Different cells respond to cAMP in different ways (Table 20-3)

How are signals amplified? Figure 20-37

How is Ca²⁺ elevated? (Figure 20-39)

Types of responses to Ca²⁺ levels (Table 20-4)

20.7 Integration and regulation of pathways

Regulation of glycogen breakdown and synthesis (Figure 20-35)

How an enzyme inegrates signals (Figure 20-43)

Regulation of blood glucose levels by glucagon and insulin (Figure 20-46)**

Ras independent protein kinase B pathway of insulin signaling (Figure 20-45)***

20.8 From Plasma membrane to nucleus

Signals lead to changes in transcription (Figure 20-48b) (Don't worry about 20-48 a)

Questions 6-9, 10-13