Single-Cell Proteomics

Proteins are treated as direct effectors of cell state because they carry abundance, localization, modification, signaling, enzymatic, and structural roles. Protein measurements in single-cell proteomics have systematic missingness because proteins cannot be sequence-specifically amplified like DNA or RNA. Proteomics datasets often have fragmented feature spaces because different platforms measure different protein panels or variable protein sets. Single-cell proteomics is challenged by sparsity and noise from mass spectrometry sampling or antibody assay background. Single-cell proteomics measures protein abundance at single-cell resolution and can reveal functional heterogeneity that transcriptomics may miss.