Continuous rearrangement of cytoskeletons and recruitment of transport vesicles to plasma membrane are thought to be essential to the growth cone motility, however, it is unclear how the proteins are directly involved in processes of axonal growth. We have recently reported of identifying 17 proteins as the functional marker proteins in the mammalian growth cone, as neuronal growth-associated proteins(nGAPs). However, it remains to be determined whether these marker proteins are widely involved in neuritogenesis in various neuronal cell types. We showed that all of the nGAPs were concentrated in the growth cone of PC12 cell. RNAi knockdown of each nGAPs also inhibited neurite elongation induced by NGF. These results indicate that nGAPs are involved in NGF-induced neurite outgrowth, and that nGAPs are very useful as generalized marker of the growth cone. To investigate the roles of nGAPs for the growth cone behavior further, we analyzed the changes of morphology of the growth cone and cytoskeletal distribution there using RNAi. We found that knockdown of some nGAPs caused significant reduction of the growth cone area and the amount of F-actin there. These results suggest that these nGAPs regulate growth cone morphology through rearrangement of F-actin and thereby control the axon outgrowth.