A unique serpin P1 ' glutamate and a conserved beta-sheet C arginine are key residues for activity, protease recognition and stability of serpinA12 (vaspin)
BIOCHEMICAL JOURNAL
Authors: Ulbricht, David; Pippel, Jan; Schultz, Stephan; Meier, Rene; Straeter, Norbert; Heiker, John T.
Abstract
SerpinA12 (vaspin) is thought to be mainly expressed in adipose tissue and has multiple beneficial effects on metabolic, inflammatory and atherogenic processes related to obesity. KLK7 (kallikrein 7) is the only known protease target of vaspin to date and is inhibited with a moderate inhibition rate. In the crystal structure, the cleavage site (P1-P1') of the vaspin reactive centre loop is fairly rigid compared with the flexible residues before P2, possibly supported by an ionic interaction of P1' glutamate (Glu(379)) with an arginine residue (Arg(302)) of the beta-sheet C. A P1' glutamate seems highly unusual and unfavourable for the protease KLK7. We characterized vaspin mutants to investigate the roles of these two residues in protease inhibition and recognition by vaspin. Reactive centre loop mutations changing the P1' residue or altering the reactive centre loop conformation significantly increased inhibition parameters, whereas removal of the positive charge within beta-sheet C impeded the serpin-protease interaction. Arg(302) is a crucial contact to enable vaspin recognition by KLK7 and it supports moderate inhibition of the serpin despite the presence of the detrimental P1' Glu(379), which clearly represents a major limiting factor for vaspin-inhibitory activity. We also show that the vaspin-inhibition rate for KLK7 can be modestly increased by heparin and demonstrate that vaspin is a heparin-binding serpin. Noteworthily, we observed vaspin as a remarkably thermostable serpin and found that Glu(379) and Arg(302) influence heat-induced polymerization. These structural and functional results reveal the mechanistic basis of how reactive centre loop sequence and exosite interaction in vaspin enable KLK7 recognition and regulate protease inhibition as well as stability of this adipose tissue-derived serpin.
Genome-Wide Association Study of Body Weight Traits in Chinese Fine-Wool Sheep
ANIMALS
Authors: Lu, Zengkui; Yue, Yaojing; Yuan, Chao; Liu, Jianbin; Chen, Zhiqiang; Niu, Chune; Sun, Xiaoping; Zhu, Shaohua; Zhao, Hongchang; Guo, Tingting; Yang, Bohui
Abstract
Simple Summary Body weight traits are economically important in the sheep industry, and it is critical to explore their underlying genetic architecture. Hence, four body weight traits, including birth, weaning, yearling, and adult weights were examined. Through a genome-wide association study on Chinese fine-wool sheep, several candidate single-nucleotide polymorphisms (SNPs) and genes were found potentially associated with the traits of interest. The results of this study may facilitate the potential use of the genes involved in growth and production traits for the genetic improvement of productivity in sheep. Abstract Body weight is an important economic trait for sheep and it is vital for their successful production and breeding. Therefore, identifying the genomic regions and biological pathways that contribute to understanding variability in body weight traits is significant for selection purposes. In this study, the genome-wide associations of birth, weaning, yearling, and adult weights of 460 fine-wool sheep were determined using resequencing technology. The results showed that 113 single nucleotide polymorphisms (SNPs) reached the genome-wide significance levels for the four body weight traits and 30 genes were annotated effectively, including AADACL3, VGF, NPC1, and SERPINA12. The genes annotated by these SNPs significantly enriched 78 gene ontology terms and 25 signaling pathways, and were found to mainly participate in skeletal muscle development and lipid metabolism. These genes can be used as candidate genes for body weight in sheep, and provide useful information for the production and genomic selection of Chinese fine-wool sheep.