Ahnak, also known as neuroblast differentiation-associated protein, is a large scaffolding phosphoprotein with a size of approximately 700 kDa. It plays diverse roles in various biological processes. It is involved in protein-protein interactions, participating in multi-protein complexes that regulate processes such as tumour suppression, immune regulation, cell architecture maintenance, and calcium homeostasis. In calcium homeostasis, it interacts with the L-type voltage-gated calcium channel (LVGCC) in excitable cells [1]. It also has implications in processes like the formation of the blood-brain barrier, cell migration, and the regulation of cardiac calcium channels [2].

In some disease-related studies, Ahnak knockout (KO) mouse models have provided insights. In liver regeneration, Ahnak KO mice showed faster liver weight-to-body weight ratio increase during the early postoperative period. Ahnak was found to enhance TGF-β signaling during liver regeneration, disrupting the cell cycle [3]. In adipocyte differentiation, Ahnak-deficient mice had smaller adipocytes, and knockdown of Ahnak in cell lines impaired adipocyte differentiation, suggesting Ahnak regulates adipogenesis through Smad1-dependent PPARγ expression [4].

In conclusion, Ahnak is a multifunctional protein involved in multiple biological processes. Studies using Ahnak KO mouse models have revealed its roles in liver regeneration and adipocyte differentiation. Its functions in calcium homeostasis, tumour suppression, and other processes also highlight its importance in understanding normal biological functions and related disease mechanisms.