Cell signaling Flashcards

1
Q

Ligand definition

A

general term for a molecule that binds to a specific site on a protein

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2
Q

receptor definition

A

protein that recognizes and respons to a signaling molecule - ligand; signal transduction

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3
Q

Agonist definiton

A

substance (ligand) that interacts with a receptor to initiate a physiological response

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4
Q

Antagonist defitition

A

Substance (ligand) that interferes with or inhibits the physiological action of another substance

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5
Q

second messenger

A

small intracellular signaling molecule generated or liberated in response to an extracellular signal

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6
Q

What can signaling molecules exhibit for a lock and key model?

A

signaling molecules exhibit some 3d structure that is complimentary to the receptor binding site

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7
Q

What does an interaction of an agonist with the binding site induce?

A

interactions of an agonist with the binding site induces a conformational shift of the receptor to a form that affects cell function

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8
Q

What can antagonists exhibit?

A

they may exhibit structural complementarity to the binding site or may interact with a different site to change receptor structure and render the receptor unresponsive to an antagonist

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9
Q

cell coupling is between

A

signaling molecules and gap junctions

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10
Q

contact-dependent is b/w?

A

signaling molecule and receptor

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11
Q

secreted molecules is b/w

A

signaling molecules and receptor

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12
Q

Cell coupling example - glucagon receptors
signal?
function?

A

glucagon receptors are not uniformly distributed on cells throughout the liver.
Signal - cAMP
Function - synchronize response to glucagon

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13
Q

Cell coupling example - cardiac muscle cells
signal?
function?

A

cardiac muscle cells are electrically coupled.
Signal - electrical conductance
function - synchronization of cardiac muscle contraction

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14
Q

Gap junction structure
6___=_____
2___= 1____
Groups of ____ = ___

A

connexin
group of 6 connexin = 1 connexon
2 connexons = 1 gap junction
groups of gap junction = plaque

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15
Q

contact-dependent signaling leukocyte example?
signal?
Receptor?
function?

A

leukocyte adhesion prior to transmigration
signal - glycoproteins on leukocytes
receptor - adhesion proteins on endothelial cells
function - attract and guide leukocytes to a site of injury

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16
Q

Contact-dependent synapse example?
Signal?
Receptor?
Function?

A

synapse formation and maintenance
signal - B-neurexin on presynaptic terminus
Receptor - neuroligin on postsynaptic cell
Function - guide and maintain synaptic proteins in close function proximity

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17
Q

Neutrophil Extravasation

PGSL1?

A

P-selectin glycoprotein 1: receptor for P-selectin

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18
Q

Neutrophil Extravasation

P-selectin

A

a cell adhesion molecule expressed in inflamation. Interaction of PGSL-1 with P-selectin on an adhered platelets leads to loose association and leukocyte rolling

19
Q

Neutrophil Extravasation

integrins

A

obligate dimers of one alpha and one beta integrin. CD11 is alpha and CD18 is beta

20
Q

Neutrophil Extravasation

ICAM-1

A

intracellular adhesion molecule 1 - a cell surface glycoprotein that binds to integrins

21
Q

Neutrophil Extravasation

PECAM-1

A

platelet endothelial cell adhesion molecule involved in leukocyte transmigration

22
Q

B-neurexin

A

(presynaptic) interacts with neuroligan (postsynpatic)

23
Q

Presynaptic scaffolding includes?

A

CASK (kinase) and MINT (adaptor) which allow for regulated and physical interactions with other members of presynpatic complex including voltage-sensitive calcium channels and SNARE proteins

24
Q

Post synaptic scaffolding includes?

A

postsynaptic density protein which physically interacts with neurotransmitter receptors to hold them in close proximity to the release site.

25
Q

Secreted molecules - hormones

signal, receptor, function

A

hormones
signal - vasopressin
receptor - vasopressin receptor
function - fluid balance

26
Q

Secreted molecules - neurotransmitters: signal, receptor, function

A

signal - acetylcholine
Receptor - nicotinic acetylcholine receptor
Function - muscle contraction

27
Q

Secreted molecule - autocoids

Signal, receptor, function

A

signal - bradykinin
receptor - bradykinin receptor
function - vasodilation

28
Q

secreted molecule - cytokines; signal, receptor, function

A
signal - interleukin 2
receptor - interleukin receptor
function - immune system
29
Q

Signaling via secreted molecules:

Endocrine, neuroendocrine, paracrine, autocrine

A

Endocrine - signaling molecule is transported via vascular circulation
Neuroendocrine - like endocrine with signaling cell being a neuron
Paracine - signaling molecule diffuses through extracellular medium to nearby cell
Autocrine signaling molecule diffuses through extracellular medium; signaling cell is also targeted

30
Q

Neuroendocrine signaling example - vasopressin or antiduretic hormone
Signal, receptors, functions

A

Signal - arginine vasopressin
receptor - VR1 on vascular smooth muscle cells or VR2 on kidney collecting duct cells
functions - increase vascular resistance and BP, increase water retention to maintain vascular volume

31
Q

Vasopressin signaling condition

A

elevated blood osmolality or low blood volume

32
Q

vasopressin signaling condition and event of hypothalamic cells do what?

A

hypothalamic neurosecretory cells respond by releasing vasopressin in posterior pituitary which enters vascular circulation

33
Q

Vasopresssin signaling V1 receptors on smooth muscle cells activation causes

A

cytosolic release of DAG and IP3 which causes contraction

34
Q

Vasopressin signaling V2 receptors in nephrons activation causes

A

increase cytosolic cAMP which induces the insertion of aquaporins allowing water retention

35
Q

Vasopressin signaling outcome

A

increase BP and stabilize fluid volume/reduce fluid loss

36
Q

Paracrine signaling - histidine induced vascular changes
signals?
receptors?
functions?

A

signal - histamine and nitric oxide
receptors - H1 on vascular endothelial cells; smooth muscle guanylyl cyclase
functions - vasodilation as a component of an inflammatory response

37
Q

Neuronal signaling neuromuscular junction - signal, receptor, functions

A

signal - acetylcholine
receptor - nicotinic acetylcholine receptor
functions - voluntary muscle contraction

38
Q

nAchR activation leads to?

A

membrane depolarization, increase cytosolic calcium and muscle contracton

39
Q

Endocrine vs synpatic signaling
Signal reached?
Concentrations?

A

endocrine - signal reaches most
synaptic - signal reaches selected cells
Endocrine - low concentrations of signaling molecules are required to activate target
Synaptic - high concentrations of signaling molecules required to activate target

40
Q

Cell surface receptors vasopressin or ADH signal, receptor, functions

A

Signal - arginine vasopressin
receptors - VR1 on vascular smooth muscle cells
VR2 on kidney collecting duct cells
functions - increase vascular resistance and BP and increase water retention to maintain retain vascular volume

41
Q

Intracellular/nuclear receptors - aldosterone regulation of electrolyte concentrations
signal?
receptor?
function?

A

signal - aldosterone (steroid hormone)
receptors - mineralcorticoid (aldosterone) receptor
functions - enhance K+ secretion and Na+ retention by kidney

42
Q

In renal collecting duct cells, aldosterone induces?

A

Aldosterone induces SGK1 expression which modulates K+ and Na+ channel activity and turnover, results in net K+ secretion along with Na+ and water retention

43
Q

Intracellular enzymes - nitric oxide to induce vasodilation example
signal, target, functions?

A

signal - NO
target - guanylyl cyclase
function - vasodilation accompanying inflammation

44
Q

Cell to cell signaling summary:
occurs?
can be targeted based on?
______dependent (2 things)

A

occurs through a variety of modalities.
Can be targeted based on - location of signal release; location of receptor; mechanism of distribution; receptor subtype.
Concentration and solubility dependent. can be manifested over a variety of time frames.