Open AccessStructure of a receptor-binding fragment of reelin and mutational analysis reveal a recognition mechanism similar to endocytic receptors
Author(s) -
Norio Yasui,
Terukazu Nogi,
Tomoe Kitao,
Yoshimi Nakano,
Mitsuharu Hattori,
Junichi Takagi
Publication year - 2007
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.0700438104
Subject(s) - reelin , endocytic cycle , receptor , ldl receptor , biology , alanine , phosphorylation , low density lipoprotein receptor related protein 8 , dab1 , mutagenesis , binding site , biochemistry , microbiology and biotechnology , mutation , gene , amino acid , lipoprotein , endocytosis , very low density lipoprotein , cholesterol
Reelin, a large secreted protein implicated in the cortical development of the mammalian brain, is composed of eight tandem concatenations of “reelin repeats” and binds to neuronal receptors belonging to the low-density lipoprotein receptor gene family. We found that both receptor-binding and subsequent Dab1 phosphorylation occur solely in the segment spanning the fifth and sixth reelin repeats (R5–6). Monomeric fragment exhibited a suboptimal level of signaling activity and artificial oligomerization resulted in a 10-fold increase in activity, indicating the critical importance of higher-order multimerization in physiological reelin. A 2.0-Å crystal structure from the R5–6 fragment revealed not only a unique domain arrangement wherein two repeats were aligned side by side with the same orientation, but also the unexpected presence of bound Zn ions. Structure-guided alanine mutagenesis of R5–6 revealed that two Lys residues (Lys-2360 and Lys-2467) constitute a central binding site for the low-density lipoprotein receptor class A module in the receptor, indicating a strong similarity to the ligand recognition mode shared among the endocytic lipoprotein receptors.