title: Localization of adenylate kinase 4 in mouse tissues.
abstract: Adenylate kinase (AK) is a key enzyme in the high-energy phosphoryl transfer reaction in living cells. Of its isoforms, AK4 has a similar sequence and subcellular localization to that of AK3 in the mitochondrial matrix. However, unlike AK3, AK4 lacks the guanosine triphosphate: adenosine monophosphate phosphotransferase activity. To elucidate the physiological role of AK4, we explored the protein localization of AK4 in various mouse tissues by immunohistochemical analysis. AK4 protein was detected in the kidney, liver, brain, heart, stomach, intestine, and gonads but not in the lung and spleen. Interestingly, cell-type specific expression was evident in the brain, gastrointestinal tract, and gonads. In the cerebellum, AK4 was detected in granular cells but not in Purkinje cell bodies. In the gastrointestinal tract, AK4 was highly expressed in epithelia. In the ovary, AK4 was detected in oocytes and corpora lutea. In the testis, AK4 was detected in spermatocytes but not in spermatogonia. Our findings demonstrate that AK4 localizes uniquely in a cell-type and tissue-specific manner in mouse tissues.
authors.affiliation: Department of Molecular Biology, Institute of Health Biosciences,The University of Tokushima Graduate School, 3-18-15 Kuramoto, Tokushima 770-8504, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Miyoshi
authors.forename: Yuki
authors.initials: Y
authors.lastname: Akazawa
authors.forename: Taigo
authors.initials: T
authors.lastname: Horiguchi
authors.forename: Takafumi
authors.initials: T
authors.lastname: Noma