Pref-1 receptor: Identification and characterization in inhibiting adipogenesis

Pref-1（Preadipocyte factor-1）是我们最初克隆和鉴定的广泛使用的前脂肪细胞标志物。Pref-1在前脂肪细胞中表达，在脂肪细胞分化过程中下调，并且在脂肪细胞中不存在。Pref-1是一种在细胞外结构域中具有6个EGF重复序列的质膜蛋白。Pref-1胞外域被TACE切割以产生具有生物活性的可溶性Pref-1。在培养的细胞中以及在小鼠体内进行的功能获得和丧失研究显示Pref-1以自分泌/旁分泌方式抑制脂肪形成。因此，尽管Pref-1消融的小鼠具有更高的脂肪组织质量，但脂肪组织中的Pref-1过表达导致部分脂肪营养不良伴异位脂肪储存。Pref-1激活MEK/ERK以诱导Sox 9，Sox 9反过来抑制C/EBPb和C/EBPd，从而抑制脂肪细胞分化。然而，启动Pref-1信号传导的质膜上的Pref-1受体尚未被鉴定。通过使用最近开发的二氮丙啶光反应性连接体结合稳健的NHS-酯化学原位，最近已经鉴定了Pref-1的推定质膜受体。本研究的目的是确定和表征Pref-1受体，这是Pref-1信号传导的最接近和关键的组分，并研究抑制脂肪细胞分化的下游组分。为了实现这一目标，将采取生物化学、细胞和分子方法以及体外和体内功能获得和丧失研究。从长远来看，阐明Pref-1结合Pref-1受体及其下游信号通路的机制将有助于开发控制脂肪生成的策略。

Pref-1 (Preadipocyte factor-1) is a widely used preadipocyte marker that we originally cloned and identified. Pref-1 is expressed in preadipocytes, downregulated during adipocyte differentiation, and is absent in adipocytes. Pref-1 is synthesized as a plasma membrane protein with 6 EGF-repeats in the extracellular domain. Pref-1 ectodomain is cleaved by TACE to generate the biologically active soluble Pref-1. Gain- and loss-of function studies in cultured cells, as well as in mice in vivo showed Inhibition of adipogenesis by Pref-1 in autocrine/paracrine manner. Thus, whereas Pref-1ablated mice have higher adipose tissue mass, Pref-1 overexpression in adipose tissue causes partial lipodystrophy with ectopic fat storage. Pref-1 activates MEK/ERK to induce Sox9, which in turn suppresses C/EBPb and C/EBPd, to inhibit adipocyte differentiation. However, the Pref-1 receptor at the plasma membrane that initiates Pref-1 signaling is yet to be identified. By using recently developed diazirine photo-reactive linker combined with robust NHS-ester chemistry in situ, the putative plasma membrane receptor for Pref-1 has recently been identified. The goal of this research is to firmly establish and characterize the Pref-1 receptor which is the most proximal and critical component of Pref-1 signaling and to study the downstream components to inhibit adipocyte differentiation. To accomplish this goal, biochemical, cellular and molecular approaches as well as gain- and loss-of function studies in vitro and in vivo will be taken. In the long run, elucidating mechanisms underlying Pref-1 binding to the Pref-1 receptor and its downstream signaling pathway will help to develop strategies to control adipogenesis.