Laminin (Ln)
isoforms may play important roles in neuronal development, particularly axon guidance, but neural receptors mediating interactions with Ln are not entirely understood. In this paper, we have compared the adhesive and process outgrowth activities of a human
neuroblastoma cell line SY5Y on various
laminin isoforms. Cell adhesion and process outgrowth were examined on murine Ln-1 (Englebreth-Holm-Swarm
sarcoma laminin), human placental Ln-1 (human Ln-1[p]), human Ln-2 (
merosin), human Ln-5 (
kalinin/
epiligrin/
nicein), and human foreskin keratinocyte extracellular matrix extract (human HFK-ECM). Ln-5 was shown to evoke process outgrowth in amounts comparable to other Ln
isoforms. Antibody perturbation experiments showed that adhesion and process outgrowth on murine Ln-1 was primarily mediated by the
integrin alpha 1 beta 1, whereas adhesion and outgrowth on human Ln-5 and human HFK-ECM were mediated by alpha 3 beta 1. Adhesion to human Ln-1(p) and Ln-2 was not blocked by addition of anti-alpha 1 or anti-alpha 3
antibodies alone, but adhesion was partially perturbed when these
antibodies were added in combination. Process outgrowth on human Ln-1(p) was blocked when either anti-alpha 3 or anti-beta 1
antibodies were added, indicating that alpha 3 beta 1 is the primary
integrin heterodimer responsible for process extension on this substrate. These results demonstrate that Ln-5 and other Ln
isoforms support comparable levels of adhesion and process outgrowth, but different
integrin heterodimers, alone and in combination, are used by SY5Y cells to mediate responses.