Characterization of a novel fungal protein, p15, which induces neuronal differentiation of PC12 cells.
In our previous paper, we reported that a 15 kDa protein (p15) produced by a fungus, genus Helicosporium, enhanced NGF-induced neurite outgrowth from PC12 cells. Here we further characterized the actions of p15. The complete amino acid sequence of p15 was determined and it was shown to be a hydrophilic protein composed of 118 amino acid residues with two intramolecular disulfide bridges. p15-induced neurite outgrowth was blocked by the depletion of extracellular Ca(2+) in the culture medium and was significantly inhibited by L-type Ca(2+) channel inhibitor nicardipine. p15 stimulated Src kinase and MAPK activities, and neurite outgrowth was not observed in srcDN2, a dominant negative c-src(K295R)-expressing cell line, and was significantly reduced in RasN17-expressing cells. These results suggest that p15 stimulates neurite outgrowth through the potentiation of L-type Ca(2+) channels, thereby activating the Src-Ras-MAPK cascade.
Wakatsuki
S
S
Department of Biotechnology, The University of Tokyo, Bunkyo-ku, Tokyo, 113-8657, Japan.
Arioka
M
M
Dohmae
N
N
Takio
K
K
Yamasaki
M
M
Kitamoto
K
K
D000595:Amino Acid Sequence; D000818:Animals; D020746:Calcium Channels, L-Type / Q000378:metabolism; D002227:Carbazoles / Q000494:pharmacology; D018797:Cell Cycle Proteins; D002454:Cell Differentiation / Q000187:drug effects*; D050762:Cyclin-Dependent Kinase Inhibitor p15; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005656:Fungal Proteins / Q000494:pharmacology*; D026121:Indole Alkaloids; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D008969:Molecular Sequence Data; D009474:Neurons / Q000166:cytology / Q000187:drug effects*; D009529:Nicardipine / Q000494:pharmacology; D016716:PC12 Cells; D051381:Rats; D014157:Transcription Factors / Q000494:pharmacology*; D025521:Tumor Suppressor Proteins
D020746:Calcium Channels, L-Type; D002227:Carbazoles; C493969:Cdkn2b protein, rat; D018797:Cell Cycle Proteins; D050762:Cyclin-Dependent Kinase Inhibitor p15; D004791:Enzyme Inhibitors; D005656:Fungal Proteins; D026121:Indole Alkaloids; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; C049985:staurosporine aglycone; D009529:Nicardipine; D020928:Mitogen-Activated Protein Kinases