Final: Ch 16 Notch/Delta, SREBP, Integration Flashcards Preview

Cellular and Molecular Biology > Final: Ch 16 Notch/Delta, SREBP, Integration > Flashcards

Flashcards in Final: Ch 16 Notch/Delta, SREBP, Integration Deck (40):
1

MMP

matrix metalloprotease

metal containing enzymes that cleave the extracellular segments of target proteins near the outer membrane

2

in the Notch/Delta pathway, ___ cleavage of the extracellular part of the Notch receptor is followed by its cleavage within the plasma membrane by a different protease, releasing the _____ domain that functions as a ___

MMP, cytosolic, TF

3

upon binding Delta, the _______ receptor is cleaved and releases a component ___

Notch, TF

4

are the receptor Notch and its ligand Delta single spanning transmembrane proteins found on the cell surface?

yes

5

when Delta on one cell binds Notch on another cell what happens

activated Notch undergoes two cleavage events

these result in the Notch cytosolic domain being released and functioning as a TF

6

2 cleavage events Notch undergoes

ADAM cleaves the extracellular segment of Notch

Secretase cleaves the cytosolic segment of Notch, which translocates to the nucleus

7

Delta and Notch are initially equivalent, but _____ Delta on the target cell and ________ expression of Delta on the source cell

decreases, increases

8

what is disintegrin

a protein domain that binds integrins and disrupts cell-matrix interactions

9

lateral inhibition

a process where adjacent cells achieve different fates

ex. Notch forms a complex with SuH to transcribe genes whose effect is on cell fate

Notch increases, and Delta decreases

10

many signaling molecules are synthesized as transmembrane proteins whose signal domain extends into the _________ region... ex.

extracellular

ex. Delta

11

many growth factors and other proteins are synthesized as transmembrane ______ whose cleavage results in....

precursors

cleavage releases soluble active signaling molecule into the extracellular space

12

what class of protein are the ADAM family and what can heightened ADAM activity result in?

MMPs

increased activity is seen in cancers (high levels of EGF, destroys ECM to facilitate metastasis)

13

inappropriate cleavage of amyloid precursor protein can lead to _________ disease

Alzheimer's disease

amyloid plaques accumulate from cleavage ofamyloid precursor protein (APP)

14

proteolysis of SREBP releases a __________ _______ that acts to maintain __________ and ________ levels

transcription factor, phospholipid, cholesterol levels

15

LDL

low density lipoprotein

rich in cholesterol and transports it through the circulatory system

16

both the cholesterol biosynthetic pathways and cellular levels of LDL receptors are ____-______ when cellular levels are adequate

down-regulated

17

SRE-binding protein (SREBP)

cholesterol-dependent transcription factors

interact with sterol regulatory elements in the promoters to modulate expression of genes

18

when cells have ______ cholesterol, SREBP is found in the ___ membrane complexed with SCAP, insig-1, and other proteins

adequate, ER membrane

19

when cholesterol levels drop sufficiently what happens

SCAP releases cholesterol and the SCAP-SREBP complex moves from the ER to Golgi via COPII vesicles

SREBP is cleaved twice and nuclear SREBP moves to the nucleus and activates transcription of genes with sterol regulatory elements in promoters

20

result of nuclear SREBP

expression of genes that import cholesterol into the cell (LDL receptor)

expression of genes that synthesize cholesterol like HMG-CoA reductase

21

does SCAP recycle back to the ER?

yes

22

what do statins do

reduce plasma LDL

bind HMG-CoA reductase to inhibit it

increase # of LDL import receptors in liver

23

maintenance of blood glucose concentration depends on which two hormones

insulin (beta cells)

glucagon (alpha cells)

24

insulin _______ the level of blood glucose

reduces

25

glucagon ______ the level of blood glucose

increases

26

what happens to blood glucose after a meal

raises above normal level, and pancreatic beta cells release insulin (binds receptors)

insulin binding insulin receptor tyrosine kinase activates protein kinase B

27

what does protein kinase B do after it's activated by insulin tyrosine kinase receptors

phosphorylates a target protein that triggers the rapid fusion of vesicles containing the glucose transporter GLUT4 with the membrane

this lowers blood sugar

28

insulin stimulation of muscles cells does what...

enhances conversion of glucose into glycogen

PKB activates glycogen synthease

29

insulin stimulation effect in liver cells...

inhibit glucose synthesis

30

when blood glucose drops normally what happens

GLUT4 receptors are internalized and glucose import lowers

31

if blood glucose drops too much what happens

glucagon is secreted in liver cells, causing a rise is cAMP --> PKA

PKA inhibits glycogen synthesis and promotes glycogenolysis to yield glucose --> released into blood

32

diabetes mellitus

deficiency in insulin released in response to increased blood sugar (type I) - autoimmune destruction of insulin producing beta cells

impaired ability of muscle/fat to respond to insulin (type II)

33

multiple signal transduction pathways interact to regulate ________ differentiation through _____ the master transcriptional regulator

adipocyte, PPAR-gamma

34

what are the major cells for storing fats

white adipocytes

35

are adipocytes also endocrine cells that secrete signaling proteins?

yes

36

PPAR-gamma

a transcription factor member of the nuclear receptor superfamily

master transcriptional regulator of adipocyte differentiation

37

a knockdown of the gene for PPAR-gamma in preadipocytes does what

prevents their differentiation into adipocytes

38

multiple extracellular signals act in concert to regulate ________, and they intersect at the master gene encoding ______

adipogenesis, PPAR-gamma

39

PPAR gamma induces expression of _/___ which...

C/EBP alpha

Makes more PPAR gamma

40

Which stem cells give rise to progenitor cells for adipocytes

Mesenchymal stem cells