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Sorting specificity of spermatogenic cell specific region of mouse hexokinase‐s ( mHk1‐s )
Author(s) -
Nakamura Noriko,
Komiyama Masatoshi,
Fujioka Makio,
Mori Chisato
Publication year - 2003
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/mrd.10215
Subject(s) - biology , complementary dna , mitochondrion , subcellular localization , microbiology and biotechnology , hexokinase , colocalization , cell fractionation , somatic cell , transfection , gene , biochemistry , cytoplasm , glycolysis , enzyme
Hexokinase is the first enzyme involved in the glycolysis process that produces glucose phosphorylate. Our previous study reported on our cloning of mouse Hk1‐s ( mHk1‐s ) cDNA, which were expressed only in testis cells, and noted that this cDNA has a spermatogenic cell‐specific region (SSR) that replaces the porin binding domain (PBD) in the Hk1 of somatic cells. Although we know that PBD binds to the outer membrane of a mitochondrion, the role of the SSR is not yet understood. To investigate the intracellular localization of SSR, we constructed expression vectors with the epitope tag (GFP‐, HA‐), subcloned SSR, or PBD cDNA. We transfected these vectors in mouse fibroblast, NIH3T3 cells, after which we observed the localization of the SSR and PBD in the NIH3T3 cells. Our current study using the immunocytochemical method revealed that PBD is concentrated around the mitochondrion. However, the SSR could not be ascribed to the mitochondrion, ER, or nuclear colocalization. Moreover, subcellular fractionation analysis showed that PBD was detected in the mitochondrial fraction, and that SSR was detected in the cytosolic fraction. Our findings suggest that PBD of Hk1 targets mitochondrion, but the SSR of mHk1‐s targets some specific organellae. Mol. Reprod. Dev. 64: 113–119, 2003. © 2003 Wiley‐Liss, Inc.