Signalling Flashcards
Integrator Proteins
Protein product of cell surface receptors at that start a cascade of reactions
Latent Gene regulator proteins
proteins that can be stored to initiate a later rapid response
Scaffold protein
adaptor/anchoring proteins that bind proteins into a functional complex
What major effect do scaffold proteins have on cell signalling?
Increase signalling efficiency
SH2
Src homology 2 domain, bind phosphorylated tyrosines (PY)
PH
Pleckstrin homology domain, binds charged head groups of specific phosphorylated inositol phospholipids (PP) & allow proteins to dock in the membrane
PTB
Phosphotyrosine-binding domain
SH3
Src homology 3 domain, binds short proline-rich amino acid sequences (PPP)
Inositol Phospholipid
anchors protein to the membrane
PPP
Proline-rich motif
Y
tyrosine
PY
Phosphotyrosine
What are the 4 important binding domains?
PH, PTB, SH2, SH3
What are the main Motifs?
PP, PY, PPP
PP
Phosphorylated inositol phospholipid
Paracrine Signaling
form of cell-to-cell communication in which a cell produces a signal to induce changes in nearby cells, altering the behavior or differentiation of those cells
Autocrine Signaling
cell signalling in which a cell secretes a hormone or chemical messenger (called the autocrine agent) that binds to autocrine receptors on that same cell, leading to changes in the cell
Endocrine Signaling
Hormones move through the bloodstream
How do steroid hormones ender the cell to bind to intracellular receptors?
Diffuse across the Plasma Membrane
Agonist
Mimic the function of a hormone by binding a receptor and causing a normal response
Antagonists
bind to the receptor but do not induce a normal physiological response
How many membrane spanning regions do G-Protein coupled receptors contain?
7
What are the 3 “post-amplifie?r” Target proteins
Metabolic enzyme, Gene regulatory protein, cytoskeletal protein
What structures allow cell to cell communication to take place?
plasma membrane-attached proteins
Endocrine
Hormones moving through the blood stream
What are the steps in endocrine signaling?
Hormone is secreted into the blood by the endocrine gland, Hormone travels through the blood stream to the target cells, Hormone interacts with the target cells
What is unique about steroid hormone Receptors?
They all have homologous binding domains
How do steroid Hormone receptors Interact with DNA?
Through Zinc Fingers
What are the 3 major classes of Cell surface Receptors?
Ion-channel-linked receptors, G-protein-linked receptors, Enzyme-linked receptors
What are the 8 classes of large signalling proteins?
Relay proteins, Messenger proteins, Adaptor proteins, Amplifier proteins, Transducer proteins, Bifurcation proteins, Integrator proteins, Latent gene regulatory proteins
What are five ways desensitizing of target cells can take place?
Receptor sequestration, receptor down-regulation, receptor inactivation, inactivation of signaling protein, production of inhibitory protein
What are the 3 subunits of Trimeric G proteins?
alpha, beta, gamma
How to Trimeric G proteins work?
when no ligand is bound to the receptor GDP is pound to the complex, when a ligand binds to the receptor GDP is switch out for GTP, The G-alpha-GTP complex separates and interacts with an “effector”
What are adaptor proteins?
regulators of G protein signaling (RGS), enhance GTPase activity of the G-alpha-GTP complex and are know as GTPase Activating Proteins (GAPs)
Transducer
a device that converts variations in a physical quantity, such as pressure or brightness, into an electrical signal, or vice versa
