Question

QUESTION 1

1. When cells stimulate other cells at long distances, it is referred to as:

   		paracrine loops
   		autocrine loops
   		synaptic signaling
   		endocrine signaling

1 points   

QUESTION 2

1. What region of a protein binds phosphorylated serines & tyrosines on another protein?

   		SH2 domain
   		ligand
   		cAMP
   		receptor monomers

1 points   

QUESTION 3

1. Activation of a serpentine receptor can lead to:

   		cAMP generation
   		GTP-binding of G proteins
   		activation of Protein Kinase A
   		all of the above

1 points   

QUESTION 4

1. When the cytokine, Vascular Endothelial Growth Factor (VEGF), binds to the VEGF receptor, the signal transduction that occurs can signal all of these outcomes EXCEPT:

   		cell survival
   		proliferation
   		cell death
   		cell migration

1 points   

QUESTION 5

1. The main purpose of the RAS protein is to:

   		phosphorylate receptors
   		transcribe genes
   		activate MAP kinase cascades
   		block angiogenesis

1 points   

QUESTION 6

1. After being activated, STAT proteins:

   		phosphorylate receptors
   		bind to cytokines
   		form trimers
   		translocate to the nucleus

1 points   

QUESTION 7

1. How many phosphorylation events do JAKs perform after cytokine receptors are dimerized?

   		1
   		2
   		3
   		4

1 points   

QUESTION 8

1. Cytokine receptors have partially redundant functions because:

   		they share receptor subunits
   		any receptor can bind most cytokines
   		they're expressed at the same time
   		cells have a limited number of responses

1 points   

QUESTION 9

1. STAT proteins can turn on many different genes, but don't turn them ALL on at the same time even when some STATS are activated because:

   		cells don't like to be overstimulated
   		the promoters of genes are designed differently
   		not all cells have the same genes
   		sometimes STATs are exocytosed from the cell

1 points   

QUESTION 10

1. Cells can inhibit JAK/STAT signaling by:

   		dephosphorylating cytokine receptor tails using phosphatases
   		dephosphorylating STAT dimers using phosphatases
   		using proteins that bind STAT dimers to inhibit their DNA binding
   		all of the above

Answer 1

1) When cells stimulate other cells at long distances, it is referred to as:
      
Answer is: endocrine signaling

Paracrine loops are where hormones released from cells and bind to nearby receptor on nearby cells

Autocrine loops are where hormones released from cells and bind to receptor that produces it.
      
Synaptic signaling: Synaptic signaling is same as paracrine signaling but there is synapse.
      
Endocrine signaling are long distance signaling.


2) What region of a protein binds phosphorylated serines & tyrosines on another protein?

Answer is: SH2 domain

SH2 domain where protein binds and phosphyrolates serines and tyrosines of another protein that causes protein-protein interaction.

Ligand docks on the receptor, cAMP is chemical energy that drives different processes, monomer is unactivated receptor.


3) Activation of a serpentine receptor can lead to:

Answer is: all of the above

serpentine receptors activate G proteins that activate or inhibit adenylyl cyclase. It links with G-protein on the membrane inner leaflet. The activation of protein kinase C leads by activation of serpentine receptor.


4) When the cytokine, Vascular Endothelial Growth Factor (VEGF), binds to the VEGF receptor, the signal transduction that occurs can signal all of these outcomes EXCEPT:

Answer is: cell death as it does not signal cell death.


5) The main purpose of the Ras protein is to
activate MAP kinase cascades as activating Ras results inthe activation of the MAP kinase cascade.

6) After being activated, STAT proteins
translocate to the nucleus as after STATs are activated tgen it forms dimers and translocate to the nucleus. Here, they can start transctiption of genes. They are not called as kinases, thus will not phosphorylate other proteins and do not bind cytokines that are located on the outside cell.


7) How many phosphorylation events do JAKs perform after cytokine receptors are dimerized?

Answer is: 3 because they perform 3 phosphorylation events which are cross-phosphorylate the JAK; phosphorylate the receptor tail and phosphorylate the STAT protein.

8) Cytokines receptors have partially redundant functions because they share receptor subunits as cytokine receptors has redundant functions they share common receptor subunits that has same effects.


9) STAT proteins can turn on many different genes, but don't turn them ALL on at the same time even when some STATS are activated because the gene promoters are designed differently. They have selectivity in which genes are turned on as gene promoters are designed differently.