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Contactin‐associated protein (Caspr) 2 interacts with carboxypeptidase E in the CNS
Author(s) -
Oiso Shigeru,
Takeda Yasuo,
Futagawa Toshitaka,
Miura Takehiko,
Kuchiiwa Satoshi,
Nishida Kentaro,
Ikeda Ryuji,
Kariyazono Hiroko,
Watanabe Kazutada,
Yamada Katsushi
Publication year - 2009
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.2009.05928.x
Subject(s) - microbiology and biotechnology , golgi apparatus , immunoprecipitation , transfection , biology , membrane protein , immunocytochemistry , biochemistry , membrane , endoplasmic reticulum , gene , endocrinology
To identify proteins interacting with the intracellular domain of the neural cell adhesion molecule contactin‐associated protein 2 (Caspr2), yeast two‐hybrid screening was performed. We identified carboxypeptidase E (CPE) as a Caspr2‐interacting candidate protein. Glutathione S ‐transferase pull‐down and immunoprecipitation analyses indicated that Caspr2 was associated with CPE in vitro and in vivo . Both Caspr2 and CPE were expressed predominantly in the CNS. Immunohistochemical analyses revealed that both Caspr2‐ and CPE‐like immunoreactivities were found to co‐localize in the apical dendrites and cell bodies of rat cortical neurons. In subcellular localization analysis, Caspr2‐ and CPE‐like immunoreactivities were co‐migrated in the fractions of Golgi/ER. Additionally, in COS‐7 cells co‐transfected with CPE and Caspr2 cDNAs, Caspr2‐ and CPE‐immunoreactivities were co‐localized in both Golgi and membrane, whereas it was only observed in Golgi of either COS‐7 cell transfected with CPE or Caspr2 cDNA alone. It is known that the membrane‐bound form of CPE functions as a sorting receptor of prohormones in the trans ‐Golgi network. Taken together, our data suggest that CPE may be a key molecule to regulate Caspr2 trafficking to the cell membrane.