The PSI has developed numerous standardized data formats in the past 20 years and more are currently under development. An overview of the formats developed by the Molecular Interactions Working Group and their relationships to other components is summarized in Figure . The formats of the Mass Spectrometry Working Group and the Proteome Informatics Working Group and their relationships to other components are summarized in Figure . In this section we briefly describe each format, assess its current status, and provide links and citations for obtaining more information. Active formats are presented by working group, followed by non-PSI related formats and deprecated formats.