title: Mammalian selenocysteine lyase is involved in selenoprotein biosynthesis.
abstract: Selenocysteine lyase (SCL) catalyzes the decomposition of L-selenocysteine to yield L-alanine and selenium by acting exclusively on l-selenocysteine. The X-ray structural analysis of rat SCL has demonstrated how SCL discriminates L-selenocysteine from L-cysteine on the molecular basis. SCL has been proposed to function in the recycling of the micronutrient selenium from degraded selenoproteins containing selenocysteine residues, but the role of SCL in selenium metabolism in vivo remains unclear. We here demonstrate that the (75)Se-labeling efficiency of selenoproteins with (75)Se-labeled selenoprotein P (Sepp1) as a selenium source was decreased in HeLa cells transfected with SCL siRNA as compared to the cells transfected with control siRNA. Immunocytochemical analyses showed high SCL expression in kidney and liver cells, where selenocysteine is recovered from selenoproteins. Mature testes of mice exhibited a specific staining pattern of SCL in spermatids that actively produce selenoproteins. However, SCL was weakly expressed in Sertoli cells, which receive Sepp1 and supply selenium to germ cells. These demonstrate that SCL occurs in the cells requiring selenoproteins, probably to recycle selenium derived from selenoproteins such as Sepp1.
authors: Institute for Chemical Research, Kyoto University, Uji, Kyoto, Japan.
authors: Suguru
authors: S
authors: Kurokawa
authors: Masanori
authors: M
authors: Takehashi
authors: Hiromitsu
authors: H
authors: Tanaka
authors: Hisaaki
authors: H
authors: Mihara
authors: Tatsuo
authors: T
authors: Kurihara
authors: Seigo
authors: S
authors: Tanaka
authors: Kristina
authors: K
authors: Hill
authors: Raymond
authors: R
authors: Burk
authors: Nobuyoshi
authors: N
authors: Esaki
mesh_terms: D000070:Acebutolol; D000818:Animals; D006367:HeLa Cells; D006801:Humans; D007553:Isotope Labeling; D007668:Kidney / Q000378:metabolism*; D008099:Liver / Q000378:metabolism*; D008190:Lyases / Q000378:metabolism*; D008297:Male; D051379:Mice; D034741:RNA, Small Interfering / Q000378:metabolism; D051381:Rats; D012643:Selenium / Q000378:metabolism*; D017279:Selenocysteine / Q000378:metabolism*; D051149:Selenoprotein P / Q000378:metabolism; D051140:Selenoproteins / Q000096:biosynthesis* / Q000378:metabolism; D012708:Sertoli Cells / Q000378:metabolism; D013087:Spermatids / Q000378:metabolism*; D013379:Substrate Specificity; D014162:Transfection
chemical_list: D034741:RNA, Small Interfering; D051149:Selenoprotein P; D051140:Selenoproteins; D017279:Selenocysteine; D000070:Acebutolol; D008190:Lyases; C034278:selenocysteine lyase; D012643:Selenium