Student: Karen O’Hare*, Amanda Rea*, Neil Doppler and Amy Buonaccorsi
Mentor: Mark Jareb
Previous data suggest that a laminin receptor is localized in the axons of chick forebrain neurons mediating the axon-growth promoting properties of laminin. Many heterodimers from the integrin family of proteins have previously been identified as laminin receptors, including the α6β4 heterodimer. We tested the role of β4, β1, and α6 integrins in laminin-induced increases in axonal growth using function blocking antibodies. Axons of neurons grown on laminin treated with β4 integrin antibodies or α6 integrin antibodies were significantly shorter compared to untreated cultures or cultures treated with a β1 integrin function-blocking antibody. These data are consistent with the hypothesis that the α6β4 heterodimer acts as the axonal laminin receptor in embryonic chick forebrain neurons. To directly test whether β4 integrin was localized to axons, we expressed in cultured forebrain neurons from embryonic chick both, a β4 integrin-GFP construct and a β4 integrin construct in which the cytoplasmic tail has been deleted. In both cases, β4 integrin expression was visualized in axons. These data suggest that β4 integrin is targeted to axons and the signal for this targeting is not dependent on its cytoplasmic region.
* Honors Senior