Peterson Jonathan M, Wei Zhikui, Wong G William
Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
Biochem Biophys Res Commun. 2009 Oct 16;388(2):360-5. doi: 10.1016/j.bbrc.2009.08.014. Epub 2009 Aug 8.
C1q/TNF family comprises over thirty secreted multimeric proteins that play diverse and important roles in immune, endocrine, skeletal, neuronal, reproductive, sensory, and vascular systems. Here we describe two novel human C1q/TNF family members, designated as CTRP8 and CTRP9B. Both genes are absent in the mouse genome. CTRP8 is expressed predominantly in lung and testis. In addition to forming homotrimers, CTRP8 also forms heteromeric complexes with C1q-related factor (CRF). CRF is a secreted multimeric protein that forms heteromeric complexes with CTRP1, CTRP9, and CTRP10. Although human CTRRP9A and CTRP9B share 98% amino acid identity, they are encoded by distinct genes and are biochemically distinct. While CTRP9A is robustly secreted as a multimeric protein, CTRP9B requires physical association with CTRP9A or adiponectin for its secretion. We propose here that combinatorial association between C1q/TNF family members is a possible mechanism to generate an expanded repertoire of functionally distinct ligands with altered function and/or receptor specificity.
C1q/TNF家族由三十多种分泌型多聚体蛋白组成，它们在免疫、内分泌、骨骼、神经、生殖、感觉和血管系统中发挥着多样而重要的作用。在此，我们描述了两个新的人类C1q/TNF家族成员，命名为CTRP8和CTRP9B。这两个基因在小鼠基因组中均不存在。CTRP8主要在肺和睾丸中表达。除了形成同三聚体外，CTRP8还与C1q相关因子（CRF）形成异源复合物。CRF是一种分泌型多聚体蛋白，可与CTRP1、CTRP9和CTRP10形成异源复合物。尽管人类CTRRP9A和CTRP9B具有98%的氨基酸同一性，但它们由不同的基因编码，并且在生物化学性质上有所不同。CTRP9A作为多聚体蛋白能大量分泌，而CTRP9B的分泌需要与CTRP9A或脂联素发生物理结合。我们在此提出，C1q/TNF家族成员之间的组合关联可能是一种机制，用以产生功能不同且功能和/或受体特异性发生改变的配体库。
