Molecular characterization of MARTA1, a protein interacting with the dendritic targeting element of MAP2 mRNAs

• Published in: Journal of neurochemistry Vol. 82; no. 5; pp. 1039 - 1046
• Main Authors: Rehbein, Monika, Wege, Konstanze, Buck, Friedrich, Schweizer, Michaela, Richter, Dietmar, Kindler, Stefan
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01.09.2002; Blackwell
• Subjects: Animals; Biological and medical sciences; Cell Nucleus - metabolism; cell polarity; Cell structures and functions; Cells, Cultured; Cytoplasm - metabolism; Cytoskeleton, cytoplasm. Intracellular movements; Dendrites - metabolism; extrasomatic translation; Fundamental and applied biological sciences. Psychology; Humans; Microtubule-Associated Proteins - genetics; Molecular and cellular biology; Molecular Sequence Data; Nerve Tissue Proteins - genetics; Nerve Tissue Proteins - metabolism; Neurons - cytology; Neurons - metabolism; Rats; ribonucleoprotein particle; RNA localization; RNA, Messenger - metabolism; RNA-Binding Proteins - genetics; RNA-Binding Proteins - metabolism; RNA‐binding protein; Sequence Alignment; Sequence Homology, Amino Acid; Trans-Activators; Stability; Rat; ribonucleoprotein particle; Rodentia; Central nervous system; RNA binding protein; extrasomatic translation; RNA localization; MARTA1 protein; Encephalon; Vertebrata; RNA-binding protein; Mammalia; Neuron; Cytoskeleton; Polarity; Microtubule associated protein; Microtubule; cell polarity
• ISSN: 0022-3042; 1471-4159
• DOI: 10.1046/j.1471-4159.2002.01058.x

In neurones, the somatodendritic microtubule‐associated protein 2 regulates the stability of the dendritic cytoskeleton. Its extrasomatic localization appears to be a multicausal mechanism that involves dendritic mRNA trafficking, a process that depends on a dendritic targeting element in the 3′ untranslated region. Two rat MAP2‐RNA trans‐acting proteins, MARTA1 and MARTA2, exhibit specific high‐affinity binding to the dendritic targeting element. We have now affinity‐purified MARTA1 from rat brain. Analysis of proteolytic peptides revealed that rat MARTA1 is the orthologue of the human RNA‐binding protein KSRP. Rat MARTA1 is a 74‐kDa protein that contains four putative RNA‐binding domains and is 98% identical to human KSRP. Both purified rat MARTA1 and human KSRP preferentially bind to the dendritic targeting element, but do not strongly interact with other investigated regions of mRNAs encoding microtubule‐associated protein 2 and α‐tubulin. In rat brain neurones and cultured neurones derived from superior cervical ganglia, MARTA1 is primarily intranuclear, but is also present in the somatodendritic cytoplasm. Thus, MARTA1 may play a role in nucleocytoplasmic mRNA targeting.