Construction of human tissue-specific phosphorylation networks with protein expression data

Phosphorylation is a post-translational modification process mediated by kinases through the addition of a covalently bound phosphate group, which plays important roles in a wide range of cellular progresses, such as signaling cascades and development. Over the past years, despite many phosphorylation sites have been determined with mass spectrometry techniques, it is not clear which kinase phosphorylates which proteins. Under the circumstance, we propose a new probabilistic model to identify the substrates phosphorylated by certain kinases. Furthermore, we construct three tissue-specific phosphorylation networks based on protein expression data. Investigating the constructed tissue-specific networks, we find they are functionally consistent with the corresponding tissues, implying the effectiveness and biological significance of our proposed approach.