GATED MIGRATION - NEURONS MIGRATE ON BUT NOT ONTO SUBSTRATES CONTAINING S-LAMININ

Components of the extracellular matrix influence migration of diverse cell types. Some, such as laminin, promote neuronal migration, whereas others are nonpermissive or inhibitory. Here, we demonstrate that a r ecombinant fragment of s-laminin, a homologue of the laminin B1 chain, is a barrier to neuronal migration, NSC-34 (motoneuron-like) and cili ary ganglion cells were plated on substrates coated with alternating s tripes of laminin and a mixture of laminin plus s-laminin. On these pa tterned substrates, cells seldom crossed from s-laminin-free to s-lami nin-containing regions. Mutation of the tripeptide LRE, an adhesive si te in s-laminin, abolished s-laminin's ability to block border crossin g. However, overall rates of migration were similar on the two substra tes. This behavior contrasts with that of previously reported barrier molecules, which decrease rates of cell migration when mixed with perm issive substrates. Instead, s-laminin appears to block cell migration through a ''gating'' mechanism that acts primarily at borders. (C) 199 5 Academic Press, Inc.