Cell Signalling

What is..?

SMAD = Small body Mothers Against Decapentaplegic

STAT = Signal Transducer and Activator and Transcription [Stat 1, 2, 3, 4, 5a, 5b, 6] like hello, bagi jela nama senang sikit

JAK = Janus Kinases [Jak 1, 2, 3, Tyk2(asal la tak letak je Jak4, gedik!)]

G protein = Guanine nucleotide binding protein [a molecular switch, active when bound to GTP and inactive when bound to GDP]

GPCR@7-span@serpentine receptor = G-protein-coupled receptor

Protaglandin E binds to at least 4 GPCR, Dopamine and acetylcholine binds to at least 5 GPCR, adrenaline@epinephrine binds to at least 9 GPCR, serotonin@5-HT binds to at least 15 GPCR

RGS protein = Regulator of G-protein Signalling


Regulation of Ras: GEF= Guanine nucleotide exchange factor, GAP = GTPase activating protein

Gs: stimulates adenylate cyclase (Glucagon, ACTH)

Gi: inhibits adenylate cyclase (Prostaglandin PGE1, adenosine), activated by acetylcholine

Gt: stimulates cGMP phosphodiesterase (Photons (rhodopsin))

Gq: stimulates phospholipase C (Bombesin, vasopressin)

G13: activates ion channels (Na⁺/H⁺ exchange)(Thrombin)

Gas: stimulate adenylate cyclase, receptor is activated by cholera toxin so the Gas constantly ON.

Gai: inhibit adenylate cyclase, activate MAPK cascades (MAPK3, MAPK2, MAPK), receptor is inactivated by Pertussis toxin so Gai constantly OFF

Gao: activate phospholipase C-b, bukak K+, tutup Ca2+

Gaq: activate phospholipase C-b, activate MAPK cascades

Gbg: opens K+ channels in cardiac muscle, causes hyperpolarisation

Adenyl cyclate converts ATP to cAMP (a second messenger)

RTK activates MAPK cascades via Ras

GPCR and RTK activate:

1. 3 isoforms of PLC: PLC-g, PLC-b and PLC-d

2. PI-3 kinases: p85, p101 and p110

Dopamine: D1-like, D2-like receptors; D1 and D5 couple via Gs stimulating adenylate cyclase; D2, D3, D4 couple via Gi inhibiting adenylate cyclase.

Acetylcholine: 5 muscarinic receptors; M1, M3, M5 couple dengan Gq to stimulate phospholipase C. M2 couples Gi to open K+ channel. M4 couples Gi to inhibit adenylate cyclase. stimulates contraction of skeletal muscle, inhibits contraction of cardiac muscle.

Nak diceritakan pasal serotonin a.k.a 5-HT tak payah la...

Sakit jiwa tak murid-murid? Jangan...thats not even 1/20 of it. Sedap nye kalau bley mengajar budak sekolah menengah benda macam nie, merasa la kau! Rabbi yassir wa la tu 'assir.