The 2015 Gordon Conference on Posttranslational Modification Networks will present cutting-edge research on the protein aspects of the cellular systems. A decade of research empowered by genomic technologies has generated a huge amount of information about genes and gene expression. However, our understanding of the cellular systems is limited by our ability to analyze the composition, behavior and regulation of the gene products, proteins. Protein function is modulated by a myriad of covalent modifications that can only be studied at the protein level. Advances in mass spectrometry are breaking this bottleneck and thus making proteomics one of the most exciting areas of life science research. The Conference will feature a wide range of topics, such as detection and quantitative analysis of protein posttranslational modifications (PTMs, including protein phosphorylation, ubiquitination, glycosylation, alkylation, as well as novel PTMs), and signal transduction and cellular regulation through PTM networks in biology of humans, animals and plants. The Conference will focus on mass spectrometry approaches but will also include computation and systems biology approaches. Invited speakers are at the forefront of their field and represent a variety of scientific disciplines, including mass spectrometry, animal and medical sciences, and plant sciences. The Conference, with programmed discussion sessions, poster sessions, as well as opportunities for informal gatherings in the afternoons and evenings, provides an avenue for scientists from different disciplines to brainstorm and develop cross-disciplinary collaborations. The Conference will provide opportunities for junior scientists and graduate students to present their work in poster format and exchange ideas with leaders in the field. Some poster presenters will be selected for short talks.