Myelinated nerve fibres

Communication breakdown

Problems in cell signalling can be bad news

When messages between cells are blocked or scrambled, there are usually harmful results. Autoimmune diseases, in which our own immune cells attack body tissues, are partly caused by errors in identifying cells. In multiple sclerosis, misdirected T cells remove the electrically insulating sheath around neuronstumours begin when cells ignore signals telling them not to replicate or when they misread signals to keep dividing. Teratomas (tumours that can contain hair, teeth and bone) arise from germ cells (sperm and eggs) that are triggered to begin dividing inside the body.

Some diseases affect cell–cell signalling directly. In Alzheimer’s disease, toxic clumps of a protein called amyloid appear in the brain. They build up from fragments of a precursor protein present at synapses, which is abnormally processed.

Another example is diabetes. In type 1 diabetes, sugar metabolism gets out of control because the cells that make the hormone insulin die off. In the more common type 2 diabetes, there is insulin in the circulation, but the cells that normally respond to it do not respond to the signal.

Lead image:

Myelinated nerve fibres.

Dr David Furness/Wellcome Images CC BY NC

Further reading

About this resource

This resource was first published in ‘The Cell’ in February 2011 and reviewed and updated in September 2015.

Topics:
Cell biology, Health, infection and disease
Issue:
The Cell
Education levels:
16–19, Continuing professional development