Lecture 7 & 8 (growth factors)

Question 1

Functional division of oncoproteins

Answer 1

1. Growth factors
2. Tyrosine kinases
3. Guanine nucleotide binding proteins
4. Serine/threonine kinases
5. Nuclear oncoproteins
6. Tumour suppressor proteins

Question 2

What does the sis oncogene code for?

Answer 2

PDGF B chain

Question 3

Cells must express __ to be responsive to sis transformation

Answer 3

PDGF receptor

Question 4

PDGF-A and -B related peptides show __% amino acid homology

Answer 4

~40%

Question 5

Growth factors with oncogenic potential

Answer 5

• PDGF family: A chain, B chain (sis)
• FGF family: acidic & basic FGF, int-2, hst, FGF-5
• EGF family: EGF, TGFα
• Int-1 (Wnt)
• Haematopoietic growth factors: T cell growth factor (IL-2), multipotential CSF (IL-3), CSF-1, GM-CSF

Question 6

Acidic & basic FGF are related polypeptides with __% amino acid identity

Answer 6

~50%

Question 7

How was int-2 discovered?

Answer 7

by insertional mutagenesis by MMTV in mouse mammary tumours

Question 8

How was hst discovered?

Answer 8

by gene transfer (focus assay, hst gene isolated from human stomach cancer)

Question 9

What do int-2, hst and FGF-5 have to facilitate insertion into the ER for secretion?

Answer 9

a hydrophobic signal sequence in NH2 terminus

Question 10

Acidic and basic FGF function to __ __

Answer 10

repair wounds (they lack a hydrophobic sequence and are not secreted)

Question 11

What is Neu differentiation factor (NDF)?

Answer 11

A glycoprotein belonging to the EGF family that causes differentiation of mammary tissue and production of milk (also called Heregluin)

Question 12

EGF domain contains six __ residues

Answer 12

cysteine

Question 13

How many ErbB ligands are known?

Answer 13

at least 11

Question 14

ErbB is also known as __

Answer 14

EGFR

Question 15

3 groups of ErbB ligands

Answer 15

1. EGF, Amphiregulin (AREG), TGF-α, Epigen
2. Betacellulin, HB-EGF, epiregulin (EPR)
3. Neuregulins (Heregulins)
   - NRG1 and NRG2
   - NRG3 and NRG4