Nucleobindin-2 Is a Positive Modulator of EGF-Dependent Signals Leading to Enhancement of Cell Growth and Suppression of Adipocyte Differentiation

Abstract

Nucleobindin-2 is a 420-amino-acid EF-hand calcium-binding protein that undergoes proteolytic processing to generate an 82-amino-acid amino-terminal peptide termed nesfatin-1. To determine whether nucleobindin-2 has any biological function, nucleobindin-2 was either overexpressed or knocked down by short hairpin RNA in cultured CHO cells expressing the human insulin and epidermal growth factor (EGF) receptors (CHO/IE) and in 3T3-L1 cells. Reduction in nucleobindin-2 expression inhibited EGF-stimulated MAPK kinase (S217/S221) and Erk phosphorylation (T202/Y204). In contrast, there was no significant effect on EGF-stimulated EGF receptor phosphorylation, EGF receptor internalization, or 52-kDa Shc and c-Raf phosphorylation. Although kinase suppressor of Ras-1 and protein phosphatase 2A expression was not changed, intracellular calcium concentrations and PP2A activity was significantly increased in nucleobindin-2 knocked-down cells. Concomitant with these alterations in EGF-stimulated signaling, cell proliferation was significantly reduced in nucleobindin-2 knocked-down cells. Moreover, reduced nucleobindin-2 expression in 3T3-L1 preadipocytes resulted in a greater extent of 3T3-L1 cell adipocyte differentiation. Taken together, these data indicate that nucleobindin-2 regulates EGF-stimulated MAPK kinase/Erk signaling, cell proliferation, and adipocyte differentiation.

Hypothalamic Nesfatin-1 Stimulates Sympathetic Nerve Activity via Hypothalamic ERK Signaling

“…Recently, in vitro experiments using a neural cell line demonstrated that nesfatin-1 stimulates the phosphorylation of MAPK (19), CREBP (20), and AMPK (11), playing important roles in regulating feeding behavior and energy metabolism in vivo (12,13,(16)(17)(18)22,23). Our in vivo finding that the ICV injection of nesfatin-1 concentration dependently increased MAPK activity (phosphorylation of ERK1/2), but not AMPK, PI3K, or CREBP activity, corroborates this finding.…”

“…Although a receptor specific to nesfatin-1 has not yet been identified, the different signaling systems mediated by nesfatin-1 have been clarified. Nesfatin-1 stimulates the phosphorylation of mitogen-activated protein kinase (MAPK) (19), CREBP (20), and AMPK (11). However, the precise signaling mechanisms underlying nesfatin-1-induced activation of the sympathetic nervous tones in the brain remain to be determined.…”

Nucleobindin 2 (NUCB2) in human endometrial carcinoma: a potent prognostic factor associated with cell proliferation and migration

“…On the other hand, in this study, we demonstrated significant phosphorylation of mTOR following nesfatin-1 treatment in Ishikawa endometrial cancer cells. Similarly, nesfatin-1 is reported to decrease ERK 1/2 phosphorylation and exert anti-proliferative effects on H295R adrenocortical carcinoma cells [20], while it is also reported that NUCB2 is a positive mediator of EGF-stimulated ERK phosphorylation [33]. It is therefore suggested that the biological function of NUCB2 may vary among tissues, and further examinations are therefore needed to clarify the molecular mechanism associated with the diverse roles of NUCB2.…”

Effect of dapagliflozin on colon cancer cell [Rapid Communication]

“…Cell viability was estimated by XTT cell proliferation assay kit [6] following manufacture's instruction (Roche Applied Science, Tokyo, Japan). Briefly seeded cells were mixed with prepared 2,3-Bis (2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carbox-anilide (XTT) working solution for 6 h at 37 °C under 5% CO 2 and absorbance value was obtained at 490 nm with a reference correction at 630 nm.…”