BIOL1040 Module 1 L3 Cell communication and receptor fams

WHat are the rwo major types of Cell signalling

Local signalling (neighbouring cells) and long distance signalling (travelling thorugh bloodstream tro rest of body)

Types of Local Signalling

Paracrine Signalling - signalling cell acts on target cells by secreting molecules of a local regulator. can also secrete molecules which itself has receptors for

Synaptic signallin - nerve cell releases neurotransmitter molecules into synapse, stimulating target cell

Types of long-distance signalling

endocrine (hormonal) signalling - hormones released into body fluids, mainly blood

what are the stages of cell signalling

Reception - cell receives signalling molecules, Transduction - cell changes the signal into a nother form within the cell, Response - activation of cellular resposne

How do signalling moelcules act on the cell

they interact with the cell receptors whcih exist on the surface of the cell or inside the cell (for hydrophobic signalling molecules)

Name the 4 receptor families

Plasma Membrane Receptors: Ion Channel receptors, G protein-coupled receptors, receptor tyrosine kinases.

Intracellular Receptors: Steroid receptors

Ion Channel Receptors

Ligand-gated ion channel - allows particles who cant diffuse normally to travel down the conc. gradient rapidly

G protein-coupled receptors

Involved in the nervous system - fast. Targetted by 50% of current drugs. Activated by Light, ions, hormones, peptides, neurotransmitters. check lecture for proper rundown

Receptor Tyrosine Kinases

E.g. Insulin receptors . Ligand binding causes dimerisation (the two receptors connect to form 1). The Tyrosine molecules in the receptor’s intracellular region are phosphorylated, which fully activated the receptor. The phosphorylated groups act as docking sites for cellular signalling proteins. Therefore, there are multiple possible signalling pathways.

Steroid receptors

Slow - acting throughout the body. Intracellular and activated by hormones. Hormone enters the cell and binds to the receptor forming a complex. this conmplex travels into the nucleus and acts as a transcription factore, changibng gene expression.