The Complex Interplay between AHNAK1 and Calcium during Early Stages of Adipogenesis in 3T3-L1 Cells

Abstract

Obesity, which is currently a major public health issue, results from excess adipose tissue. High intracellular calcium has been shown to attenuate adipogenesis in 3T3-L1 cells, a model cell line for differentiation. The scaffold protein, AHNAK1 may affect the onset of adipogenesis through its role in the phospholipase C gamma 1 (PLCγ1) signaling cascade at the plasma membrane of 3T3-L1 cells, which results in the release of intracellular calcium stores.Question: What is the effect of extracellular calcium concentration on AHNAK1 localization in preadipocytes and early adipocytes? Methods included Subcellular Fractionation Assays, Immunofluorescent Staining and Differentiating 3T3-L1 cells. In the presence of high extracellular calcium, AHNAK1 translocates from the nucleus to the plasma membrane of 3T3-L1 preadipocytes and early adipocytes, where it is able to participate in a calcium signaling cascade. In a parallel project, we found that increasing the expression of AHNAK1 resulted in increased intracellular calcium release. Knocking down AHNAK1 had the opposite result. The involvement of AHNAK1 in calcium homeostasis may present this protein as a potential therapeutic target for obesity by regulating factors that result in adipogenesis.