The N‐terminal His‐tag affects the triglyceride lipase activity of hormone‐sensitive lipase in testis

Abstract

The sterility of hormone-sensitive lipase (HSL) knockout mice clearly shows the link between lipid metabolism and spermatogenesis. However, which substrate or product of this multifunctional lipase affects spermatogenesis is unclear. We found that an HSL protein with a His-tag at the N-terminus preserved the normal hydrolase activity of cholesteryl ester (CE) but the triglyceride lipase (TG) activity significantly decreased in vitro. Therefore, mice with this functionally incomplete HSL (His-HSL) were produced on a background of HSL deficiency (HSL −/− h). As a result, HSL −/− h testis has an 8.65-fold higher CE activity than wild-type testis but a twofold higher TG activity than wild-type testis. To compare His-HSL and wild-type HSL in vitro and in vivo, we confirmed that the His-tag significantly suppressed HSL TG activity. From our results, we believe that TG activity was affected by the His-tag insertion, but CE activity was not influenced. Furthermore, the His-tag protected HSL from binding to the inhibitor BAY. From our study, TG activity and BAY binding sites were affected by N-terminal His-tag insertion. K E Y W O R D S cholesterol metabolism, hormone-sensitive lipase, lipid metabolism, male infertility, spermatogenesis

Cloning and Molecular Characterization of HSL and Its Expression Pattern in HPG Axis and Testis during Different Stages in Bactrian Camel

“…In addition, the HSL CDS sequence of Bactrian camel has a high degree of homology (no less than 90%) with other published mammalian HSL sequences from the NCBI. Previous studies have suggested that HSL may be involved in spermatogenesis and androgen synthesis in the testis [ 13 , 16 , 17 , 21 , 22 ]. However, little has been reported about the HSL function in Bactrian camels, and the mechanism of regulation is unknown.…”

Regulation of [Ca2+]i oscillations and mitochondrial activity by various calcium transporters in mouse oocytes

“…Obese, diabetic and aging women typically suffer from abnormal body metabolism such as hypertension, hyperglycemia and hyperlipidemia [19][20][21][22][23][24], causing long-term stress in oocytes [25], which severely damages the quality of oocytes, thereby leading to lower pregnancy rates [26]. Insufficient oocyte activation and mitochondrial damage were considered to be major causes for embryo developmental disorders [27,28].…”

Effects of mitochondria‐associated Ca2+ transporters suppression on oocyte activation

“…Abnormal body metabolism such as hypertension, hyperglycemia and hyperlipidemia will cause long‐term stress in the oocyte's endoplasmic reticulum and mitochondria, 27 which severely damages the quality of oocytes, thereby leading to lower pregnancy rates in women 28 . Oocyte activation deficiency is considered to be a major cause for fertilization failure.…”