Signaling mechanism involved in L1-[alpha]v[beta]3-mediated neurite outgrowth from PC12 cells.
Published: 2004
Language: eng
Number of pages: 142
Description: Cell adhesion molecules (CAM) play an active role during neurite outgrowth. The CAM L1 is a potent inducer of neurite outgrowth and the immunoglobulin-like domain 6 of L1 (L1-Ig6) has been found to promote neurite outgrowth from PC12 cells through interactions with the integrin alphavbeta 3. Integrin signaling is diverse yet the responses for different ligands are distinct. Integrin alphavbeta3 can bind to multiple ligands including L1, osteopontin and angiotensin. It is, therefore, of interest to determine the downstream molecules involved upon L1 interaction with integrin alpha vbeta3. Stable PC12 transfectants expressing the beta3 cytoplasmic domain (beta3c) fused to the tandem affinity purification (TAP) tag were established. Expression of the TAP-tagged beta3c inhibited L1-Ig6-induced neurite outgrowth from PC12 cells but had no effect on outgrowth induced by the extracellular matrix proteins, laminin or vitronectin. Capping experiments suggest that the association of alphavbeta3 with the cytoskeleton was impaired in beta3c-TAP transfectants. Activation of alpha vbeta3 by a ligand induces clustering of alpha vbeta3 and initiates a phosphotyrosine cascade that ultimately leads to association with the cytoskeletal network. The beta3c-TAP fusion protein likely titrated key signaling proteins involved in alphavbeta 3-mediated neurite outgrowth. The beta3c-TAP complex was purified by tandem affinity purification and the proteins were analyzed by MALDI-TOF mass spectrometry. A major component of the beta3c-TAP complex was the serine/threonine kinase, ILK. ILK is a focal adhesion molecule that has been implicated in regulating neurite outgrowth in a variety of neuronal cells. Therefore, ILK may be an important mediator of L1-alphavbeta3-mediated neurite outgrowth from PC12 cells.
Notes: Adviser:  Chi-Hung Siu.

Thesis (M.Sc.)--University of Toronto, 2004.

Electronic version licensed for access by U. of T. users.

Source: Masters Abstracts International, Volume: 42-06, page: 2208.

MICR copy on microfiche (2 microfiches).