4.1N binding regions of inositol 1,4,5-trisphosphate receptor type 1

• Published in: Biochemical and biophysical research communications 2006-04, Vol.342 (2), p.573-576
• Main Authors: Fukatsu, Kazumi, Bannai, Hiroko, Inoue, Takafumi, Mikoshiba, Katsuhiko
• Format: Article
• Language: English
• Subjects: 4.1N; Animals; Binding Sites; Calcium Channels - metabolism; Cells, Cultured; Cercopithecus aethiops; COS Cells; CTM1; CTT14aa; Cytoskeletal Proteins - metabolism; Diffusion; Genes, Reporter; Immunoprecipitation; Inositol 1,4,5-Trisphosphate - metabolism; Inositol 1,4,5-trisphosphate receptor type 1; Inositol 1,4,5-Trisphosphate Receptors; Membrane Glycoproteins - metabolism; Membrane Proteins - metabolism; Neuropeptides - metabolism; Protein Binding; Protein Structure, Tertiary; Rats; Receptors, Cytoplasmic and Nuclear - metabolism
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/j.bbrc.2006.02.010

Zhang et al. and Maximov et al. [S. Zhang, A. Mizutani, C. Hisatsune, T. Higo, H. Bannai, T. Nakayama, M. Hattori, and K. Mikoshiba, Protein 4.1N is required for translocation of inositol 1,4,5-trisphosphate receptor type 1 to the basolateral membrane domain in polarized Madin-Darby canine kidney cells, J. Biol. Chem. 278 (2003) 4048–4056; A. Maximov, T. S. Tang, and I. Bezprozvanny, Association of the type 1 inositol (1,4,5)-trisphosphate receptor with 4.1N protein in neurons, Mol. Cell. Neurosci. 22 (2003) 271–283.] reported that 4.1N is a binding partner of inositol 1,4,5-trisphosphate receptor type 1 (IP 3R1), however the binding site of IP 3R1 differed: the former determined the C-terminal 14 amino acids of the cytoplasmic tail (CTT14aa) as the binding site, while the latter assigned another segment, cytoplasmic tail middle 1 (CTM1). To solve this discrepancy, we performed immunoprecipitation and found that both the segments had binding activity to 4.1N. Both segments also interfered the 4.1N-regulated IP 3R1 diffusion in neuronal dendrites. However, IP 3R1 lacking the CTT14aa (IP 3R1-ΔCTT14aa) does not bind to 4.1N [S. Zhang, A. Mizutani, C. Hisatsune, T. Higo, H. Bannai, T. Nakayama, M. Hattori, and K. Mikoshiba, Protein 4.1N is required for translocation of inositol 1,4,5-trisphosphate receptor type 1 to the basolateral membrane domain in polarized Madin-Darby canine kidney cells, J. Biol. Chem. 278 (2003) 4048–4056.] and its diffusion constant is larger than that of IP 3R1 full-length in neuronal dendrites [K. Fukatsu, H. Bannai, S. Zhang, H. Nakamura, T. Inoue, and K. Mikoshiba, Lateral diffusion of inositol 1,4,5-trisphosphate receptor type 1 is regulated by actin filaments and 4.1N in neuronal dendrites, J. Biol. Chem. 279 (2004) 48976–48982.]. We conclude that both the CTT14aa and CTM1 sequences can bind to 4.1N in peptide fragment forms. However, we propose that the responsible binding site for 4.1N binding in full-length tetramer form of IP 3R1 is CTT14aa.