Identification of protein partners of acidic calponin

Abstract

The up-regulation of acidic calponin gene in different brain tumors has been revealed by a bioinformatic tool termed Oncoreveal. Expression pattern has been further confirmed with an independent brain tumor panel by our group members. Previous studies reported the interaction of acidic calponin with Smad1/5 and the negative effect of this interaction on TGF /BMP signaling pathway. A link between TGF /BMP signaling pathway activation and reduction of brain tumor populations, hints at a role of acidic calponin in tumorogenesis. Moreover, non-tissue specific expression of acidic calponin raised our interest in investigating the function of acidic calponin in liver cells. As a starting point, identification of protein partners of acidic calponin by using yeast two hybrid screening was performed. Screening pretransformed human liver cDNA library resulted in the identification of ring finger protein 10 (RNF10) and RAS p21 protein activator (RASA1) proteins. The interaction between RNF10 and acidic calponin was further verified by coexpression and co-immunoprecipitation experiments. Elucidation of protein partners, which is the main aim of this study, may provide clues about the role of acidic calponin in liver cells. Due to the cross communication of TGF /BMP signaling pathway with variety of signaling pathways at different stages further studies may be conducted to investigate the function of acidic calponin in different signaling pathway context, too.