Lecture 24 - Cancer Genetics 2 (Signaling Pathways and Intervention) Flashcards
Which is NOT a function of SH2 domain containing proteins?
A. Recruit SH2 proteins to the plasma membrane
B. Provide docking sites for association with other proteins
C. Bind proline rich sequences of 9 or 10 residues
D. Promote phosphorylation of associated proteins
E. Stimulate enzyme activity of associated proteins
C. SH3 domains are a second motif of SOME proteins that dock to activated RTKs, and these bind proline rich sequences.
___________ are the largest family of enzyme linked receptors.
Receptor tyrosine kinases
The most common amino acids phosphorylated by protein kinases are ______ and ______.
- serine
- threonine
*Note: phosphorylation of tyrosine occurs less frequently
The structure of tyrosine kinase receptors has 3 major parts. What is the function of the N-terminal?
Extracellular ligand binding domain
The structure of tyrosine kinase receptors has 3 major parts. What is the function of the C-terminal domain?
Cytosolic; protein tyrosine kinase activity
The structure of tyrosine kinase receptors has 3 major parts. What are they?
- N-terminal (extracellular ligand binding domain)
- Single ‘transmembrane’ domain
- C-terminal (cytosolic site of protein TK activity)
Most receptors are ____(a)____ but some receptors, such as ___(b)___ are dimers consisting of two polypeptide chains.
a) monomeric
b) insulin
The process in which a ligand binds to the extracellular domain of the RTK and cross-links the receptor is called:
dimerization
The 2 main types of ligand induced dimerization are:
- auto-phosphorylation
2. cross phosphorylation
Ligand induced dimerization serves to: (2 functions)
- increase receptor kinase activity
2. create binding sites for specific proteins that transduce the intracellular signal
_____(a)_____ are binding sites for a unique set of intracellular proteins that utilize select domains called ____(b)_____.
a) Phosphotyrosine sites
b) SH2 domains
What protein generates diacylglycerol (DAG) and inositol 1,4,5-triphosphate (IP3)?
Phospholipase C-gamma
Which product generated by phospholipase C-gamma (PLC-gamma) functions to activate serine/threonine protein kinases?
DAG
Which product generated by phospholipase C-gamma (PLC-gamma) binds to ligand-gated Ca2+ channel receptors triggering release of intracellular stores of Ca2+ from the ER?
IP3
The ________ pathway activates RTKs by mobilizing a family of serine/threonine protein kinases.
MAPK
The founding member of the MAPK family is the _______.
extracellular signal regulated protein kinase 1/2 (ERK-1/2)
The Ras proteins belong to the large super family of:
monomeric GTPases
The Ras proteins contain a covalently attached prenyl group that helps to perform what function?
Anchor the protein in the membrane
The Ras protein cycles from __(a)__ to __(b)__.
a) GDP bound inactive form
b) GTP bound active form