Secreted nucleobindin-2 inhibits 3t3-L1 adipocyte differentiation

Nucleobindin-2 is a 420 amino acid ef-hand ca2+ binding protein that can be further processed to generate an 82 amino terminal peptide termed nesfatin-1. to examine the function of secreted nucleobindin-2 in adipocyte differentiation,cultured 3t3-l1 cells were incubated with either 0 or 100 nm of gst,gst-nucleobindin-2,prior to and during the initiation of adipocyte differentiation. nucleobindin-2 treatment decreased neutral lipid accumulation (oil-red o staining) and expression of several marker genes for adipocyte differentiation (pparγ,ap2,and adipsin). when nucleobindin-2 was constitutively secreted into cultured medium,camp content and insulin stimulated creb phosphorylation were significantly reduced. on the other hand,intracellularly overexpressed nucleobindin-2 failed to affect camp content and creb phosphorylation. taken together,these data indicate that secreted nucleobindin-2 is a suppressor of adipocyte differentiation through inhibition of camp production and insulin signal. © 2012 bentham science publishers.