Molecular & Cellular Proteomics (MCP) publishes papers based on original research that are judged, after editorial review, to make a substantial contribution to the understanding of any area of proteomics. MCP also publishes short reviews and perspective articles by invitation from the Editors. These differ primarily in that the former must be a balanced presentation of the topic while the latter may reflect 'a point of view.' On occasion, at the discretion of the Editors, articles that describe activities or issues that impact proteomic research may be acceptable as Reports. MCP will accept letters to the Editor, which must address material that has appeared in the journal. The decision to publish a letter will be made by the Editors and Associate Editors and authors of papers that are addressed in any letter will be given an opportunity to respond. In all categories, authors are urged to keep the length of papers/communications to the minimum size necessary for clarity in presenting results and interpretations. For more information, go to https://www.mcponline.org/.