We use redundant peptide counting as a tool to compare, quantitatively, data from mass spectrometry analyses. When combined with hierarchical clustering, a tool commonly used for micro array analysis, we can group proteins based on their relative abundance across samples. In this way, we recently completed a spatial map of the secretory pathway of rat hepatic cells comprising some 1400 different proteins, each with a defined distribution (Gilchrist, Au, Hiding et al. 2006 Cell 127 126581). Using the same approach, we have now analyzed the secretome of mouse embryonic fibroblasts that were differentiated, in vitro, into adipocytes. By comparing the secretome of such adipocytes taken from mouse knock-in or knock outs of FOXC2, a transcription factor that when over expressed, shifts white adipose tissue towards brown adipose tissue (Cederberg et al. Cell 106 56373), we have identified several secreted factors that are distinct for each mouse strain. Their relevance to white and brown adipose tissue will be discussed.
03 - 07 May 2008
European Society of Endocrinology