B2.080 Regulating the Activity of Transcription Factors

Question 1

what mechanisms can be used to regulate transcription factors?

Answer 1

developmentally
ligands
post translational modification

Question 2

describe developmental regulation of TFs

Answer 2

some TFs are ubiquitously expressed, some are cell type specific
expression of lineage specific TFs drive cell lineage fate

Question 3

what are the lineage determining factors for cardiomyocytes?

Answer 3

NKX2-5
GATA4
TBX2
TBX5
Baf60c

Question 4

How are cytoplasm resident nuclear hormone receptors activated?

Answer 4

ligand binds and facilitates movement into nucleus

TF is then free to bind DNA and recruit co-activators to help initiate transcription

Question 5

what determines which enzymes a nuclear hormone receptor (NHR) binds?

Answer 5

tissue where NHR is acting

many remodeling complexes have different expression in different tissues

Question 6

characterize selective estrogen receptor modulator drugs (SERMs)

Answer 6

have mixed agonist and antagonist activity

based upon tissue-specific interactions between ER and HATS/HDACs/CRCs

Question 7

how are nuclear resident nuclear hormone receptors regulated?

Answer 7

normal binding to DNA exhibits repressive effect

when ligand binds to receptor, HDAC is released and HATs/CRCs are recruited

Question 8

what are example cytoplasm resident and nuclear resident NHRs?

Answer 8

cyto: glucocorticoid & estrogen receptors
nuclear: thyroid hormone, vitamin D, & retinoic acid receptors

Question 9

what are examples of post translational modifications that can increase/decrease TF activity?

Answer 9

phosphorylation, acetylation, methylation, etc.

Question 10

what are 4 schemes of post translational modification regulation of TFs

Answer 10

1. TF bound to anchor protein in cytoplasm, modification released TF to nucleus
2. TF is resident in cytoplasm, modification directly sends it to the nucleus
3. TF is bound to DNA, modification alters function (binding partners)
4. TF stability is affected by modification

Question 11

describe the nuclear factor kappa B pathway

Answer 11

bacteria surface molecules bind to cell receptors
signally cascade activated a kinase which phosphorylated IKB, releasing NFkB
NFkB moves to nucleus and upregulated genes coding for an immunoresponse