Hi everybody!

I found some interesting information about what I'm working with at the lab and I thougt that it could be interesting to tell you something about the subject and to give you some links, as well. The idea is: which is the role of integrins in neuronal migration? (We were talking about integrins and platelets).

The integrin beta1 is a transmembrane heterodimeric receptor that plays an important role in neuronal migration. This protein has many different functions related with the interaction between the cell and its environment. Yet there are two main ways in which this integrin is involved in neuron growth:

1. it is the one responsible for the attachment of the cell to the extracellular matrix,
2. and it also permits the cell to be continuously exploring its surrounding to 'decide' which path it has to follow to get the target.

Laminin is the ligand that binds to integrin to anchor the cell to the extracellular matrix (ECM). As Schmidt et al. could demonstrate in 1995, lamellipodia (leading edge) are the regions which contain the greatest concentration of integrins that exert a force over the substrate. This means that receptors located here are responsible for the traction force that enables neuron movement. Actin filaments push forward the cell membrane in a step-by-step manner due to the action of myosins (Kress et al. 2007), while integrins are being fixed to the substrate. Then, those which get the base of the growth cone are packaged by endocytosis and transported to the front once again, showing a periodic cicle similar to that of actin monomers (see figure). This agrees with the idea that integrins represent a physical bond between the cytoskeleton of the cell and the ECM.

On the other hand, this receptor has a second important function by enabling the neuron to stablish a communication with the environment. The concentration of ligands surrounding the neuron determine the way that the cell should take. So, integrins become, in that sense, the 'nose' of the neuron.