Structure and function of SPP/SPPL proteases: insights from biochemical evidence and predictive modeling

Research output: Contribution to journalReview articleContributedpeer-review


  • Sabine Höppner - , Augsburg University (Author)
  • Bernd Schröder - , Institute of Physiological Chemistry, Institute for Physiological Chemistry (Author)
  • Regina Fluhrer - , Augsburg University (Author)


More than 20 years ago, signal peptide peptidase (SPP) and its homologues, the signal peptide peptidase-like (SPPL) proteases have been identified based on their sequence similarity to presenilins, a related family of intramembrane aspartyl proteases. Other than those for the presenilins, no high-resolution structures for the SPP/SPPL proteases are available. Despite this limitation, over the years bioinformatical and biochemical data have accumulated, which altogether have provided a picture of the overall structure and topology of these proteases, their localization in the cell, the process of substrate recognition, their cleavage mechanism, and their function. Recently, the artificial intelligence-based structure prediction tool AlphaFold has added high-confidence models of the expected fold of SPP/SPPL proteases. In this review, we summarize known structural aspects of the SPP/SPPL family as well as their substrates. Of particular interest are the emerging substrate recognition and catalytic mechanisms that might lead to the prediction and identification of more potential substrates and deeper insight into physiological and pathophysiological roles of proteolysis.


Original languageEnglish
Pages (from-to)5456-5474
Number of pages19
JournalThe FEBS journal
Issue number23
Publication statusPublished - 8 Dec 2023

External IDs

Scopus 85173989737



  • Peptide Hydrolases/genetics, Membrane Proteins, Artificial Intelligence, Aspartic Acid Endopeptidases/chemistry, Presenilins