Characterization of the NF2 protein merlin and the ERM protein ezrin in human, rat, and mouse central nervous system.
The neurofibromatosis 2 (NF2) protein, merlin, is structurally related to the ERM (ezrin-radixin-moesin) protein family of membrane-cytoskeleton linkers and is mutated in nervous system tumors. Apart from tumor suppressor activity, merlin's functions are poorly understood. We compared the localization and expression of merlin and ezrin in developing and adult brain and in brain-derived progenitor cells. Both proteins were widely but differentially expressed in human, rat, and mouse brain. In brain tissue and neuronal progenitor cell cultures merlin was predominantly found in neurons while ezrin was expressed in astrocytes. Merlin expression was seen from E11 in mouse embryos, whereas ezrin was present earlier. Both proteins were expressed in embryonic mouse neurospheres, where ezrin was specifically localized in filopodia of adherent neuronal progenitor cells. Subcellular analysis demonstrated ezrin in fine filopodial structures in astrocytes, while merlin was detected in neuronal synaptic junctions. The widespread expression of merlin in brain and its association with protein kinase A suggest a role for merlin in brain biology.
Grönholm
Mikaela
M
Neuroscience Program, Biomedicum Helsinki, University of Helsinki and Helsinki University Central Hospital, PB 63, Haartmaninkatu 8, 00014 Helsinki, Finland. mikaela.gronholm@helsinki.fi
Teesalu
Tambet
T
Tyynelä
Jaana
J
Piltti
Katja
K
Böhling
Tom
T
Wartiovaara
Kirmo
K
Vaheri
Antti
A
Carpén
Olli
O
D000818:Animals; D001921:Brain / Q000196:embryology / Q000254:growth & development / Q000378:metabolism*; D002478:Cells, Cultured; D002490:Central Nervous System / Q000196:embryology / Q000254:growth & development / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D003598:Cytoskeletal Proteins; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics; D004622:Embryo, Mammalian; D006801:Humans; D051379:Mice; D025581:Neurofibromin 2 / Q000096:biosynthesis / Q000737:chemistry* / Q000235:genetics / Q000502:physiology; D010750:Phosphoproteins / Q000096:biosynthesis / Q000737:chemistry* / Q000235:genetics; D051381:Rats; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics; D000099149:Ezrin
D017868:Cyclic AMP-Dependent Protein Kinases; D003598:Cytoskeletal Proteins; D004268:DNA-Binding Proteins; D025581:Neurofibromin 2; D010750:Phosphoproteins; D014157:Transcription Factors; D000099149:Ezrin; C086680:ETV5 protein, human; C513242:Etv5 protein, mouse; C513243:Etv5 protein, rat