Final 3 Flashcards by steve aspery

Exocytosis that requires an external signal, a specific sorting signal on the vesicles, a clathrin coat, and increase of calcium

Regulated exocytosis

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Exocytosis that serves to release components of ECM or just deliver newly PM proteins

Constitutive exocytosis

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Why would a lysosome deposit its contents outside the cell?

Defense mechanism

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Mark organelles and membrane domains in late secretory pathway

Phsophoinositides

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What adds a phosphate onto the inositol ring of phosphatidylinositol

Lipid kinase

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What removes a phosphate on the inositol ring of phsophatidylinositol?

Lipid phosphatase

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How is neurotransmitter secretion very rapid?

Regulated by calcium

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WHere does proteolytic processing occur?

Late Golgi

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What holds SNARE proteins “partially-zipped up”

Complexin

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Calcium snesor protein that allows the release of vesicle content by membrane fusion

Syanptotagmin

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Example of compound exocytosis which provides a very large release of material over a short period of time

Histamines from mast cells

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What kind of cells contain GLUT4

Insulin responsive cells (adipose, muscle)

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Two compositionally distinct and different PMs

apical, basolateral

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Where is the decision of what membrane a vesicle should go to in a polarized cell made?

TGN or all go to one membrane, and undergo endocytosis and sorting

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How is iron transported into the cell?

Transferrin receptor

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Fluid-phase endocytosis for uptake of fluids and solutes

Pinocytosis

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Coat protein responsible for majority of vesicular traffic between TGN and PM

Clathrin

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Composition of clathrin coats

Triskelion: 3 heavy chains and 3 light chains

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Coat used for pinocytosis

Caveolae

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Polyhedral superstructures that clathrin triskelion form

Cages

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GTPase that constricts the neck of a newly formed coated pit to form a vesicle

Dyanmin

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How is a clathrin coat removed?

HSP70 family of chaperones and its ATPase actiity

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Storage form of cholesterol and primary vehicle for cholesterol transport in blood

Low-density lipoprotein (LDL)

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Where in the cell are LDL particles broken down?

Lysosome

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Clusters of LDL receptors in the PM

Coated pits

What does the cytosolic portion of LDL receptors do once associated with clathrin adapters?

Nucleates binding of a few clathrin triskelions to form coated pit

What happens to LDL receptors after endocytosis

Recycled into PM

How is LDL freed from its receptor?

pH change due to endosome

Separates and sequesters material to be degraded from material to be recycled

Mulitvesicular bodies (MVBs)

How are proteins recognized as needed to be degraded in MVBs?

Monoubiquination

Cytosolic protein complex that results in a specific accumulation of tagged protein into endosomal membrane invagination

ESCRT proteins

Ingestion of large particles restricted to macrophages and neutrophils

Phagocytosis

Movement of endocytosed material across the entire clel in membrane enclosed compartment

Transcytosis

What do cells unstimulated by insulin do?

Import glucose through the transporter

What do cells stimulated by insulin do?

Release glucose through exocytosis

Chemical bond formation linked to membrane transport process

Chemiosmotic coupling

High-energy electrons from NADH used to set up a proton gradient across IMM

Electron transport chain

Beta-barrel proteins on OMM

Porin

What size molecules are porins permeable to?

<5,000 daltons

Location of TCA and the source of NADH

Matrix

What is the movement of mitochondria mediated by?

Microtbulues

What generates more energy, FADH2 or NADH?

NADH

How many electrons does a NAD+ accept?

iElectrochemical gradient of protons in the mitochondria

Proton motive force (PMF)

What is the real name for ATP synthesis via electron transport chain

Oxidative phosphorylation

What does the complete oxidation of one glucose yield?

2 NADH, 2 ATP, 2 pyruvate

What are 2 pyruvates oxidized to?

8 NADH, 2 FADH, 2 GTP

How many ATPs are produced per glucose?

What kind of pump is ATP synthase?

F-type ATPase

Mobile electron carrier that can carry 1 or 2 electrons and is embedded into the membrane

Uniquinone

How is uniquinone embedded into the membrane?

Isoprenoid

What does uniquinone shuttle electrons to and from

From complex I to complex III

Soluble protein with bound heme group

Cytochrome c

What does cytochrome c shuttle electrons to and from

complex III to complex IV

Name of complex I

NADH dehydrogenase

Name of complex III

Cytochrome bc1

Name of complex IV

Cytochrome oxidase

Uncouple electron transport from ATP synthesis

Proton ionophores

2 examples of uncouplers

DNP, FCCP

Part of ATP synthesase that is intermembrane

Part of ATP synthesase that surrounds stalk with 6 subunits

Name of complex II

Succinate dehydrogenase

What does complex II do?

Accepts two electrons from succinate

Signaling to self

Autocrine

Local signaling to a close group of cells

Paracrine

Signaling distributed throughout bloodstream

Endocrine

Signaling based on physical contact

Contact dependent signaling

Difference between endocrine and synaptic signaling

Endocrine are long-livd

Most direct path of ligand signaling

Intracellular receptors (e.g. steroid hromones)

Why are steroid hormones able to use intracellular receptors?

They are lipid soluble so can pass right through PM

4 examples of small G-proteins

Ras, Rab, Rho, Ran

How many transmembrane domains do G-protein receptors have?

What happens when GDP-bound g-proteins are turned on?

ALpha dissociates from beta-gamma

What is the alpha subunit of g-proteins postranslationally modified by?

Myristic acid

What is the gamma subunit of g-proteins postranslationally modified by?

Polyisoprenoid

Enzymes that have their activity modulated by interaction with a g-protein

G-protein effectors

Enzyme that converts ATP to cAMP

Adenylyl cylcase

cAMP initiates a protein kinase cascade by activating what?

Protein Kinase A (PKA)

3 functions of cAMP

cortisol secretion from adrenal cortex, glycogen breakdown in muscle and liver, triacylglycerol breakdown in fat

In muscles, what does PKA activation lead to?

Activation of phosphorylase kinase, leading to glycogen breakdown

What gene regulatory protein does PKA activate?

cAMP regulatory element binding protein (CREB)

What does CREB do?

Changes transcription of genes that contain a cAMP regulatory element (CRE)

Enzyme that cleaves (PI(4,5)P2) into diacylglycerol and IP3

Phospholipase C-beta

What does formation of IP3 do?

Opens Ca channel and releases Ca into the cytosol from ER

After opening by IP3, what does released Ca bind to?

Protein Kinase C (PKC)

Where are Ca concentrations kept high?

ER and outside cell

Regulatory Ca binding protein for muscle contraction

Troponin C

Calcium sensor for neutrotransmission

Synaptotagmin

Multipurpose calcium receptor involved in many responses

Calmodulin

Structure of calmodulin

Four EF hands (ca binding domains)

Main targets of calmodulin

Protein kinases

Protein kinase involved in smooth muscle contraction

Myosin light chain kinase

Protein kinase inolved in glycogen breakdown

Phosphorylase kinase

Calcium-dependent protein kinase whose activity persists even after the calcium signal has faded

CaM Kinase II

How does ca-calmodulin activate CaM Kinase II?

BInds to inhibitory domain, liberating it

Single-span membrane proteins that oligomerize in response to ligand binding

Receptor tyrosine kinases (RTKs)

What kind of protein is the insulin receptor?

Disulfide-linked heterotetramer

What kind of protein are RTKs?

Enzymes

What is the typical method of oligomerization that RTKs undergo?

Dimerization

What does receptor oligomerization of RTKs lead to?

Activation of kinase domain by autophosphorylation

What happens once RTKs become autophosphorylated?

Receptor increases its kinase activity towards substrates

Binds specifically to phosphotyrosine in RTKs

Src Homology Region 2 domain (SH2)

Binds to proline rich motifs in RTKs

Pleckstrin Domain (PH)

What membrane lipid do PH domains associate with?

PIP3

3 enzymes recruited to PDGF receptor by its SH2 domain

PI3 kinase, Ras GAP, PLC-gamma

Primary target of Ras

Raf-1

What cascade is Raf-1 the first element of?

MAP kinase

Signal that tells a cell to divide

Mitogen

Through what molecule does Ras activation generate new membrane lipids?

PI 3-kinase

Receptors that rely on its associated kinases to cross phosphorylate one another

Tyrosine kinase associated receptors

Target of Jak kinases

STAT

Role of STAT

Regulator of gene expression

What kind of receptors do TGF-beta use?

Serine/threonine kinases

Activated TGF-beta activates what kind of gene regulatory proteins?

Smad

Ligands for receptor guanylyl cyclases

ANP, BNP

What do ANP and BNP do?

Regulate salt and water balance

What does cGMP activate?

PKG

Membrane bound singaling protein expressed on developing nerve cells

Delta

Receptor of Delta

Notch