BIO 11.09 VOCAB CELL SIGNALLING EXAM 1

Phosphatase

enzyme that dephosphorylates

Kinase

enzyme that phosphorylates

Connexon and connexin

transmembrane proteins, assemble into hexameric complexes to form gap junctions

Rab3 and Rab27

small GTPases that help vesicles localize to the active zone

V and T snares

vesicle & target membrane proteins, drive fusion with the membrane using alpha helix zippering

Synaptobrevin

v-snare protein crucial for neurotransmitter vesicle fusion

Snap25 and syntaxin

t-SNARE protein components, help vesicle fusion

Complexin

protein that binds to SNARE and acts as a brake (stops from finishing zipper)

Synaptotagmin

calcium sensing protein that acts on complexin to release the brake

Clathrin

coat protein that contributes to the triskelion “basket” shape - used for individual, not bulk, vesicle endocytosis

Dynamin

a GTPase responsible for pinching off coated vesicles from the plasma membrane - can be affected by GTP gamma s (nonhydrolyzable)

GTP gamma s

non-hydrolyzable analog of GTP

SSRIs

Selective serotonin reuptake inhibitors used as antidepressants

AMPAr

Ionotropic glutamate receptor in postsynaptic membrane, not selective, mainly sodium (passive), can be phosphorylated by camkii and let in more sodium

NMDAr

Ionotropic glutamate receptor found on postsynaptic membrane, has magnesium blockers, requires depolarization event to remove, needs glutamate and glycine to work, has calcium channel

GABAr

ionotropic receptors that often let in chloride ions (hyperpolarization)

Beta-gamma complex

part of g-protein that helps regulate ion channels

GIRK

Potassium channel that leads to efflux of K+ and hyperpolarization when activated by beta-gamma complex

CaV

Voltage-gated calcium channel that opens in response to membrane depolarization, can be inhibited by beta-gamma complex

PKA

kinase activated by cAMP

PDE

enzyme that converts cAMP to AMP

Arrestin

protein that binds to phosphorylated GPCRs (done by GRK) and endocytoses them

PLC

an enzyme that cleaves PIP2 into IP3 and DAG

PIP2

membrane phospholipid cleaved by PLC

PKC

kinase activated by pairing with calcium and DAG

Calmodulin

calcium-activated (both from IP3 and NMDA), binds to and activates kinases including CaMKII

CamKII

kinase activated by calmodulin, phosphorylates things like AMPArs and impacts synaptic plasticity

CREB

transcription factor phosphorylated by PKA (and sometimes CamKII) that increases synaptic plasticity

exteroception

perceiving stimuli outside the body

interoception

perceiving stimuli inside the body

polypeptide

chain of amino acids (long)

peptide

chain of amino acids (short)

peptide bond

covalent bond between carboxyl group and amino group of two amino acids

r group

unique side chain (polar, nonpolar, charged characteristics)

hydrophobic effect

when nonpolar r-group amino acids end up on the middle of a structure

primary structure

amino acid sequences

secondary structure

local folding (alpha helices, beta sheets)

tertiary structure

long-range folding, single polypeptide

quaternary structure

assembly of multiple polypeptides

supramolecule

complex held together through non-covalent association (like protein-protein interactions)

domain

distinct structural unit inside a protein that can have ligands bind

motif

small recurring sequence in a protein/nucleic acid

coding region

codes for and determines amino acid sequence

regulatory region

controls when and how much a gene is expressed

amyloid cascade hypothesis

proposes that accumulation of amyloid-beta peptides start alzheimer’s

transcription factors

proteins that bind to regulatory regions and regulate gene expression

scaffolding

recruiting and bringing together proteins, vesicles, etc to make processes more efficient (ex. bring vesicles to active zone)

integral membrane proteins

amphipathic proteins that contain transmembrane domain and often have alpha helices

peripheral membrane proteins

directly associated with membrane and/or integral proteins

lipid-anchored proteins

proteins anchored in the membrane (anchors can be exposed or not), can be extracellular or in cytoplasm

AIS

region where action potential fires first

voltage sensor domain

domain in a voltage-gated channel that senses changes in membrane potential

excitatory receptors

receptors that increase likelihood of an action potential, typically letting in cations

inhibitory receptors

receptors that decrease likelihood of an action potential, typically letting in anions

myelin sheath

insulation wrapped around axons by glial cells, speeds up and gives energy

saltatory conduction

rapid jumping of an action potential from nodes

nodes of ranvier

uninsulated gaps in myelin sheath where voltage-gated ion channels are concentrated

glial cells

non-neuronal cells that provide structural support and make up the myelin sheath

electrical synapses

gap junctions, protein channels made of connexins that allow cytoplasm sharing

emergent property of gap junctions

simultaneous AP firing/potential matching

reflexive circuits

circuits, ex. in aplysia, that involve motor, inter, and sensory neurons and give reflexes without conscious processing

reserve pool

pool of vesicles further back in cytoplasm

readily releasable pool

pool of vesicles docked at active zone and ready to fuse

docking

vesicle arrival at membrane

priming

preparation of a vesicle for fusion

active zone

site on presynaptic membrane where vesicles dock, prime, and exocytose

antiporter

transport protein that moves two different types of molecules in opposite directions across a membrane (one uphill one downhill)

symporter

transport protein that moves two different types of molecules in the same direction across a membrane (one uphill one downhill)

alpha helix zippering

when alpha helices on SNARE proteins wind together and trigger membrane fusion

clathrin-mediated endocytosis

individual vesicle endocytosis method (bulk is independent and ultrafast)

small molecules

class of neurotransmitter that is fast, in clear vesicles, and acts over very short distance (ex. glutamate, serotonin)

neuropeptides

class of neurotransmitter that is slower, in dense core vesicles, and diffuses over longer diffusions (extrasynaptic signaling)

glutamate

primary excitatory neurotransmitter

gaba and glycine

primary inhibitory neurotransmitters

acetylcholine

primary neurotransmitter at neuromuscular junctions

dopamine

reward neurotransmitter

serotonin

mood neurotransmitter

enzymatic conversion

changing a neurotransmitter to active/inactive (ex. acetylcholine → choline)

quantal units

step function of increase of synaptic strength, measured by vesicle fusion

effector proteins

proteins that produce an actual effect (ex. adenylyl cyclase, ion channel)

second messenger

a signalling molecule released to relay instructions inside a cell (ex. cAMP, IP3)

cAMP

second messenger synthesized from ATP, activates PKA, deactivated into AMP by PDE

adenylyl cyclase

effector impacted by alpha-s or alpha-i, converts ATP to cAMP

presynaptic GPCRs

GPCRs that often inhibit action potential and neurotransmitter release

crosstalk

alpha-s and alpha-i BOTH working on adenylyl cyclase activity at the same time

IP3

second messenger that binds to ER receptors and triggers calcium release

DAG

second messenger that helps calcium activate PKC

GRK

kinase that phosphorylates GPCRs, which gets them recognized by arrestin for endocytosis