Critical role of collapsin response mediator protein-associated molecule CRAM for filopodia and growth cone development in neurons

Azusa Hotta, Ryoko Inatome, Junichi Yuasa-Kawada, Qingyu Qin, Hirohei Yamamura, Shigeru Yanagi

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39 Citations (Scopus)


Collapsin response mediator proteins (CRMPs) have been implicated in signaling of axonal guidance, including semaphorins. We have previously identified a unique member of this gene family, CRMP-associated molecule CRAM (CRMP-5), which is phylogenetically divergent from the other four CRMPs. In this study, we have examined the distribution and function of CRAM in developing neurons. Immunohistochemical analysis showed accumulation of CRAM in the filopodia of growth cones. Experiments using cytochalasin D indicated that filopodial localization of CRAM was independent of filamentous actin. Overexpression of CRAM in neuronal cells significantly promoted filopodial growth and led to the formation of supernumerary growth cones, which acquired resistance to semaphorin-3A stimulation. Finally, knockdown of CRAM by using RNA interference blocked filopodial formation and revealed an aberrant morphology of growth cones. We propose that CRAM regulates filopodial dynamics and growth cone development, thereby restricting the response of growth cone to repulsive guidance cues.

Original languageEnglish
Pages (from-to)32-39
Number of pages8
JournalMolecular biology of the cell
Issue number1
Publication statusPublished - Jan 1 2005


All Science Journal Classification (ASJC) codes

  • Molecular Biology
  • Cell Biology

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