Colm Cunningham lecture 7 (Cell-cell communication)

which autoinducers do gram negative bacteria use in quorum sensing?

acyl homoserine lactone

which autoinducers do gram positive bacteria use in quorum sensing?

oligopeptides

which enzyme produces AHL in bioluminescence QS

LuxI

which protein functions as a transcriptional regulator in bioluminescence QS and together with AHL enables transcription of the lux operon

LuxR

which enzyme is the product of LuxA and LuxB genes from the lux operon and catalyses the biochemical reaction that generates bioluminescence?

luciferase

which bacteria does bioluminescence QS happen in and which species of marine animal can get colonised by it?

aliivibrio fischeri and hawaiian bobtail squid

why do aliivibrio fischeri bacteria have bioluminescence?

to evade predation

two types of cell-cell contact dependent signalling

signalling via gap junctions and contact dependent signalling

types of cell-cell signalling via secreted molecules

autocrine, paracrine, endocrine and neurotransmission

are cytokines and example of paracrine or endocrine signalling?

paracrine

what is the equivalent to gap junctions in plants?

plasmodesmata

a network of individual cells in cardiac muscle connected by gap junctions that allow them to function as a single, coordinated unit called the … …

functional syncytium

cardiomyocytes acting as a functional syncytium allows for … …

synchronous depolarisation

what is the name of the individual transmembrane proteins and are the building blocks of gap junction channels?

connexins

what is the name of the hexamer of connexins?

connexon

what is the name of the complete intercellular channels that connect two neighbouring cells in animals?

gap junctions

what do two connexons from two separate cell form when they join?

gap junction channel

two structures important in cardiac muscle contraction found at intercalated discs

gap junctions and desmosomes

a cell structure which anchors adjacent cells together, preventing cardiomyocytes from pulling apart during the hish stress contraction of the heart

desmosome

what is the name of the ER extensions which connect the ERs of two adjacent cells?

desmotubules

what are desmotubules in plasmodesmata surrounded by?

cytoplasmic sleeves

what are the four examples of molecules which move through plasmodesmata?

proteins, mRNA, gene silencing signals and metabolites

plasmodesmata are important in plants for:

1. control of … …

2. … transport

1. developmental programming

2. vascular

INDUCTION OF IMMUNE RESPONSE

1. juxtacrine signalling: an antigen is attached to a … on … … cells (APCs)

2. CD4 T cells are stimulated by antigen presentation and trigger the release of …

3. autocrine signalling: this … released binds the T cell …

4. this stimuates activation, … and … of this specific T cell clone

1. MHCII, antigen presenting

2. interleukin 2

3. IL2, IL2R

4. proliferation and differentiation

examples of paracrine signalling:

1. … released by immune cells

2. … released to drive patterning during development

3. … released locally for communication between neurons

1. cytokines

2. morphogens

3. neurotransmitters

… proteins act as morphogens by secretion and formation of gradients within tissues, where cells respond in a concentration-dependent manner, therefore establishing … specificity and …

WNT, positional, patterning

WNT PROTEINS AND HOW THEY ALTER GENE EXPRESSION

1. Wnt protein binds to two receptors; … and … and these together form the … … complex

2. binding of Wnt activated the intracellular protein …

3. … blocks the protein complex which usually destroys … alowing it to accumulate in the cytoplasm

4. … then moves to the … where it helps activate transcription of Wnt target genes

1. frizzled, LRP5/6, Wnt receptor

2. dishevelled

3. dishevelled, beta catenin

4. beta catenin, nucleus

at the neuromuscular junction, what kind of depolarisation is induced by acetylcholine binding to nicotinic receptors?

end plate potential

end plate potential at the NMJ causes opening of … … … channels which leads to an influx of … and generation of an … …

voltage gated Na+, Na+, action potential

INSULIN PRODUCTION

1. insulin gene is transcribed into …

2. ribosomes on the … translate it into …

3. … is processed into … and transported to …

4. in … granules, … is cleaved into … and …

5. it is stored in … vesicles until release

GLUCOSE TRIGGERED INSULIN RELEASE

1. glucose enters beta cells through … transporter

2. glucose it metabolised to produce …

3. increased … levels close … … … channels

4. this depolarises the membrane, opening … … … channels

5. … enters the cell, which triggers … of insulin-containing vesicles

1. mRNA

2. rER, preproinsulin

3. preproinsulin, proinsulin, golgi

4. secretory, proinsulin, insulin and C peptide

5. secretory

1. GLUT2

2. ATP

3. ATP, ATP sensitive K+

4. voltage gated Ca2+ channels

5. Ca2+, exocytosis