Signal Peptide Peptidase-Like 2c (SPPL2c) impairs vesicular transport and cleavage of SNARE proteins

EMBO Rep. 2019 Mar;20(3):e46451. doi: 10.15252/embr.201846451. Epub 2019 Feb 7.

Abstract

Members of the GxGD-type intramembrane aspartyl proteases have emerged as key players not only in fundamental cellular processes such as B-cell development or protein glycosylation, but also in development of pathologies, such as Alzheimer's disease or hepatitis virus infections. However, one member of this protease family, signal peptide peptidase-like 2c (SPPL2c), remains orphan and its capability of proteolysis as well as its physiological function is still enigmatic. Here, we demonstrate that SPPL2c is catalytically active and identify a variety of SPPL2c candidate substrates using proteomics. The majority of the SPPL2c candidate substrates cluster to the biological process of vesicular trafficking. Analysis of selected SNARE proteins reveals proteolytic processing by SPPL2c that impairs vesicular transport and causes retention of cargo proteins in the endoplasmic reticulum. As a consequence, the integrity of subcellular compartments, in particular the Golgi, is disturbed. Together with a strikingly high physiological SPPL2c expression in testis, our data suggest involvement of SPPL2c in acrosome formation during spermatogenesis.

Keywords: SNARE; SPP/SPPL‐family; glycosyltransferases; intramembrane proteases; spermatogenesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acrosome / metabolism
  • Animals
  • Aspartic Acid Endopeptidases / metabolism*
  • Biocatalysis
  • Down-Regulation
  • Glycomics
  • Glycoproteins / metabolism
  • Glycosyltransferases / metabolism
  • Golgi Apparatus / metabolism
  • HEK293 Cells
  • Humans
  • Male
  • Membrane Proteins / metabolism*
  • Mice, Inbred C57BL
  • Models, Biological
  • Protein Transport
  • Proteolysis
  • SNARE Proteins / metabolism*
  • Spermatids / metabolism
  • Subcellular Fractions / metabolism
  • Substrate Specificity

Substances

  • Glycoproteins
  • Membrane Proteins
  • SNARE Proteins
  • Glycosyltransferases
  • Aspartic Acid Endopeptidases
  • SPPL2C protein, human
  • Sppl2c protein, mouse
  • signal peptide peptidase