Proline-rich proteins are widely present in plants and play important roles in plant growth and development as well as environmental adaptation. TaPRP1 was identified as a novel and conserved Triticeae-specific proline-rich protein. Overexpressing TaPRP1 in wheat increased grain weight by 21%. TaPRP1-GFP fusion protein was localizated in both the cytoplasm and nucleus. Spatiotemporal expression analysis showed that TaPRP1 predominantly expressed in ovary and seeds with the highest expression level detected in seeds at three days post-anthesis. In yeast two-hybrid, TaPRP1 interacted with an ubiquitin protein. The involvement of TaPRP1 in ubiquitination was confirmed by RNA-Seq analysis.