Functional differences between two DCLK splice variants

• Published in: Brain research. Molecular brain research. Vol. 120; no. 2; pp. 103 - 114
• Main Authors: Engels, Bart M., Schouten, Theo G., van Dullemen, Joost, Gosens, Ilse, Vreugdenhil, Erno
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 05.01.2004; Elsevier
• Subjects: Alternative Splicing; Amino Acid Sequence; Ania-4; Animals; Biological and medical sciences; Blotting, Western - methods; Brain - anatomy & histology; Brain - metabolism; Calcium-Calmodulin-Dependent Protein Kinases - classification; Calcium-Calmodulin-Dependent Protein Kinases - genetics; Calcium-Calmodulin-Dependent Protein Kinases - physiology; CARP; Chlorocebus aethiops; Cloning, Molecular - methods; COS Cells; Cpg16; DCX; Development; DNA Mutational Analysis - methods; Fundamental and applied biological sciences. Psychology; Gene Expression; Genetic Variation; Immunohistochemistry - methods; In Situ Hybridization - methods; Male; Molecular Sequence Data; Nerve Tissue Proteins - classification; Nerve Tissue Proteins - genetics; Nerve Tissue Proteins - physiology; Neuroblastoma; Phosphorylation; Phosphotransferases - metabolism; Precipitin Tests - methods; Protein-Serine-Threonine Kinases; Proteins - metabolism; Rats; Rats, Wistar; Splicing; Transfection - methods; Vertebrates: nervous system and sense organs; PBS; DCLK; CARP; CaMK; Splicing; DTT; Ania-4; MT; Cellular and molecular biology; EDTA; CaM; bp; EGTA; GFP; CREB; HEPES; FCS; Development; DCX; MBP; Cpg16; SP; Ca; PCR
• ISSN: 0169-328X; 1872-6941
• DOI: 10.1016/j.molbrainres.2003.10.006

Recently, we have cloned two splice variants of the doublecortin-like kinase (DCLK) gene, called DCLK-short-A and -B, both of which encode calcium/calmodulin-dependent protein kinase (CaMK)-like proteins with different C-terminal ends. Using in situ hybridization, we have found that both are highly expressed in limbic structures of the brain and that their expression differs in a number of brain areas. DCLK-short-A is relatively more strongly expressed than DCLK-short-B in the subependymal zone. The DCLK-short-B variant shows stronger expression in the cortex, the ventromedial and dorsomedial hypothalamic nuclei, the arcuate nucleus, the zona incerta and the subincertal nucleus. Also, within the hippocampus, the relative distribution of these two splice variants differs. DCLK-short-B expression compared to DCLK-short-A is highest in the CA1 area. The expression of the A variant is highest in the CA3/CA4 area. Additionally, DCLK-short-B is expressed at a higher level than DCLK-short-A in the substantia nigra and the mammillary nucleus. Both DCLK-short-A and -B were located in the cytoplasm, however DCLK-short-B was also found specifically in growth cone like structures and near the nucleus. Both DCLK-short proteins phosphorylate autocamtide and syntide, two highly specific CaMK substrates. Finally, removal of the C-terminal end of DCLK-short leads to a 10-fold increase of kinase activity, indicating that the different C-termini represent auto-inhibitory domains. Our results indicate that DCLK-short-A and -B control different neuronal processes that overlap with those controlled by CaMKs.