ABSTRACT
Introduction Cell m o tility plays an im p o rtan t role in th e developm ent, regeneration and plasticity o f
tissues. O n e p ro m in en t exam ple is th e ou tgrow th o f axons and dendrites-collectively referred to as n eu n te s w hen they are grow ing-to establish neuronal connections d u rin g developm ent, w hich is a prerequisite for functional neural netw orks o f th e ad u lt organism . N eu rite o u t grow th im plies th a t the distal parts o f the processes, th e grow th cones (for a com prehensive review o f neuronal grow th cones and their m igration , see Ref. 1), sense extracellular cues fo r navigation. Cell surface adhesion molecules, extracellular m atrix proteins and polypeptide grow th factors act as cues fo r grow th cone navigation an d are therefore o f fundam en ta l im portance in a ttem pts to und ers tan d th e fo rm ation o f neuronal connections o n the m olecular level (for a review, see Ref. 2). Cell surface pro teins in teracting w ith th e com ponen ts o f the extracellular m atrix represent m ainly fo u r p ro te in families: in tegrins, m em brane-attached proteoglycans, im m u n o g lo b u lin superfam ily m em bers and recep tor-type phosphatases (Fig. 1).
