Submitted on March 17, 2003
Revised on June 6, 2003
Accepted on June 10, 2003
Seminolipid and its precursor/degradative product, galactosylalkylacylglycerol, in the testis of saposin A- and prosaposin-deficient mice
Keiko Tadano-Aritomi, Junko Matsuda, Hirokazu Fujimoto, Kunihiko Suzuki, and Ineo Ishizuka
Department of Biochemistry, Teikyo University School of Medicine, Tokyo 173-8605
Corresponding Author: kta{at}med.teikyo-u.ac.jp
Sphingolipid activator proteins (saposins A, B, C and D) are derived from a common precursor protein (prosaposin) and specifically activate in vivo degradation of glycolipids with short carbohydrate chains. A mouse model of prosaposin deficiency (prosaposin–/–) closely mimics the human disease with an elevation of multiple glycolipids. The recently developed saposin A–/– mice showed a chronic form of globoid cell leukodystrophy, establishing the essential in vivo role of saposin A as an activator for galactosylceramidase to degrade galactosylceramide (GalCer). Seminolipid, the principal glycolipid in spermatozoa, and its precursor/degradative product, galactosylalkylacylglycerol (GalEAG), were analyzed in the testis of the two mouse mutants by electrospray ionization mass spectrometry. Saposin A–/– mice showed the normal seminolipid level, while that of prosaposin–/– mice was ~150% of the normal level at the terminal stage. In contrast, GalEAG increased up to 10 times in saposin A–/– mice, whereas it decreased with age in the wild-type as well as in prosaposin–/– mice. These analytical findings on the two saposin mutants may shed some light on the physiological function of seminolipid and GalEAG.
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
