The Cas family docking protein, HEF1, promotes the formation of neurite-like membrane extensions

The Cas family proteins are a family of adhesion docking molecules that mediate protein-protein interactions and contribute to a number of signal transduction pathways. Recent studies of two family members, p130Cas and Sin, have suggested that they may play a role in neurite formation. The current study demonstrates that the third family member, HEF1, can also stimulate the formation of neurite-like processes, in the presence of Rho kinase inhibitors. The HEF1-promoted processes actively extend from the cell body and resemble neurites both in the manner of process extension and in the distribution of adhesion-associated molecules. The HEF1-promoted processes are dependent on the presence of an intact microtubule system and can be inhibited by co-expression of either constitutively active Rac or Cdc42 GTPase. Together, our data support a role for the Cas proteins in regulating cellular morphologies that contribute to tissue specialization.