scholarly journals The Metastable XBP1u Transmembrane Domain Defines Determinants for Intramembrane Proteolysis by Signal Peptide Peptidase

Cell Reports ◽  
2019 ◽  
Vol 26 (11) ◽  
pp. 3087-3099.e11 ◽  
Author(s):  
Sara Suna Yücel ◽  
Walter Stelzer ◽  
Alessandra Lorenzoni ◽  
Manfred Wozny ◽  
Dieter Langosch ◽  
...  
Keyword(s):  
Signal Peptide ◽  
Transmembrane Domain ◽  
Intramembrane Proteolysis ◽  
Signal Peptide Peptidase

scholarly journals The metastable XBP1u transmembrane domain defines determinants for intramembrane proteolysis by signal peptide peptidase

2018 ◽  
Author(s):  
Sara Suna Yücel ◽  
Walter Stelzer ◽  
Alessandra Lorenzoni ◽  
Manfred Wozny ◽  
Dieter Langosch ◽  
...  
Keyword(s):  
Signal Peptide ◽  
Transmembrane Domain ◽  
Chain Complex ◽  
Peptide Bond ◽  
Intramembrane Proteolysis ◽  
Signal Peptide Peptidase ◽  
Cellular Assays ◽  
Nascent Chain ◽  
The Unfolded Protein Response ◽  
The Impact

SummaryUnspliced XBP1 mRNA encodes XBP1u, the transcriptionally inert variant of the unfolded protein response (UPR) transcription factor XBP1s. XBP1u targets its mRNA-ribosome-nascent-chain-complex to the endoplasmic reticulum (ER) to facilitate UPR activation and prevents overactivation. Yet, its membrane association is controversial. Here, we use cell-free translocation and cellular assays to define a moderately hydrophobic stretch in XBP1u that is sufficient to mediate insertion into the ER membrane. Mutagenesis of this transmembrane (TM) region reveals residues that facilitate XBP1u turnover by an ER-associated degradation route that is dependent on signal peptide peptidase (SPP). Furthermore, the impact of these mutations on TM helix dynamics was assessed by residue-specific amide exchange kinetics, evaluated by a semi-automated algorithm. Based on our results, we suggest that SPP-catalyzed intramembrane proteolysis of TM helices is not only determined by their conformational flexibility, but also by side chain interactions near the scissile peptide bond with the enzyme’s active site.

scholarly journals Biochemical Properties of a Putative Signal Peptide Peptidase from the Hyperthermophilic Archaeon Thermococcus kodakaraensis KOD1

2005 ◽  
Vol 187 (20) ◽  
pp. 7072-7080 ◽  
Author(s):  
Rie Matsumi ◽  
Haruyuki Atomi ◽  
Tadayuki Imanaka
Keyword(s):  
Substrate Specificity ◽  
Signal Peptide ◽  
Biochemical Characterization ◽  
Transmembrane Domain ◽  
Biochemical Properties ◽  
Peptidase Activity ◽  
Amino Acid Residues ◽  
Hyperthermophilic Archaeon ◽  
Signal Peptide Peptidase ◽  
Putative Signal Peptide

ABSTRACT We have performed the first biochemical characterization of a putative archaeal signal peptide peptidase (SppATk) from the hyperthermophilic archaeon Thermococcus kodakaraensis KOD1. SppATk, comprised of 334 residues, was much smaller than its counterpart from Escherichia coli (618 residues) and harbored a single predicted transmembrane domain near its N terminus. A truncated mutant protein without the N-terminal 54 amino acid residues (ΔN54SppATk) was found to be stable against autoproteolysis and was examined further. ΔN54SppATk exhibited peptidase activity towards fluorogenic peptide substrates and was found to be highly thermostable. Moreover, the enzyme displayed a remarkable stability and preference for alkaline pH, with optimal activity detected at pH 10. ΔN54SppATk displayed a Km of 240 ± 18 μM and a V max of 27.8 ± 0.7 μmol min−1 mg−1 towards Ala-Ala-Phe-4-methyl-coumaryl-7-amide at 80°C and pH 10. The substrate specificity of the enzyme was examined in detail with a FRETS peptide library. By analyzing the cleavage products with liquid chromatography-mass spectrometry, ΔN54SppATk was found to efficiently cleave peptides with a relatively small side chain at the P-1 position and a hydrophobic or aromatic residue at the P-3 position. The positively charged Arg residue was preferred at the P-4 position, while substrates with negatively charged residues at the P-2, P-3, or P-4 position were not cleaved. When predicted signal sequences from the T. kodakaraensis genome sequence were examined, we found that the substrate specificity of ΔN54SppATk was in good agreement with its presumed role as a signal peptide peptidase in this archaeon.

scholarly journals The α-Helical Content of the Transmembrane Domain of the British Dementia Protein-2 (Bri2) Determines Its Processing by Signal Peptide Peptidase-like 2b (SPPL2b)

2011 ◽  
Vol 287 (7) ◽  
pp. 5156-5163 ◽  
Author(s):  
Regina Fluhrer ◽  
Lucas Martin ◽  
Bärbel Klier ◽  
Martina Haug-Kröper ◽  
Gudula Grammer ◽  
...  
Keyword(s):  
Signal Peptide ◽  
Transmembrane Domain ◽  
Signal Peptide Peptidase ◽  
Helical Content

scholarly journals Signal-peptide-peptidase-like 2a is required for CD74 intramembrane proteolysis in human B cells

2014 ◽  
Vol 451 (1) ◽  
pp. 48-53 ◽  
Author(s):  
Janna Schneppenheim ◽  
Susann Hüttl ◽  
Anne Kruchen ◽  
Regina Fluhrer ◽  
Ingo Müller ◽  
...  
Keyword(s):  
B Cells ◽  
Signal Peptide ◽  
Intramembrane Proteolysis ◽  
Signal Peptide Peptidase ◽  
Human B Cells

scholarly journals Substrate determinants of signal peptide peptidase-like 2a (SPPL2a)-mediated intramembrane proteolysis of the invariant chain CD74

2016 ◽  
Vol 473 (10) ◽  
pp. 1405-1422 ◽  
Author(s):  
Susann Hüttl ◽  
Felix Helfrich ◽  
Torben Mentrup ◽  
Sebastian Held ◽  
Akio Fukumori ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Signal Peptide ◽  
Invariant Chain ◽  
Transmembrane Segment ◽  
Intramembrane Proteolysis ◽  
Signal Peptide Peptidase ◽  
Luminal Membrane

Intramembrane proteolysis of CD74 by SPPL2a is essential for B- and dendritic cells. We show that CD74 is proteolysed in the luminal third of the transmembrane segment and identify determinants within its transmembrane and luminal membrane-proximal domain facilitating this cleavage.

Molecular insights into mechanisms of intramembrane proteolysis through signal peptide peptidase (SPP)

2010 ◽  
Vol 427 (3) ◽  
pp. e1-e3 ◽  
Author(s):  
Bernd Schröder ◽  
Paul Saftig
Keyword(s):  
Membrane Protein ◽  
Signal Peptide ◽  
Cell Signalling ◽  
Dominant Negative ◽  
Signal Peptides ◽  
Intramembrane Proteolysis ◽  
Independent Manner ◽  
Interacting Protein ◽  
Signal Peptide Peptidase ◽  
Signalling Molecules

The processing of membrane-anchored signalling molecules and transcription factors by RIP (regulated intramembrane proteolysis) is a major signalling paradigm in eukaryotic cells. Intramembrane cleaving proteases liberate fragments from membrane-bound precursor proteins which typically fulfil functions such as cell signalling and regulation, immunosurveillance and intercellular communication. Furthermore, they are thought to be involved in the development and propagation of several diseases, such as Alzheimer's disease and hepatitis C virus infection. In this issue of the Biochemical Journal, Schrul and colleagues investigate the interaction of the endoplasmic reticulum-resident intramembrane cleaving SPP (signal peptide peptidase) with different type II oriented transmembrane proteins. A combination of co-immunoprecipitation experiments using wild-type and a dominant-negative SPP with electrophoretic protein separations under native conditions revealed selectivity of the interaction. Depending on the interacting protein, SPP formed complexes of different sizes. SPP could build tight interactions not only with signal peptides, but also with pre- and mis-folded proteins. Whereas signal peptides are direct substrates for SPP proteolysis, the study suggests that SPP may be involved in the controlled sequestration of possibly toxic membrane protein species in a proteolysis-independent manner. These large oligomeric membrane protein aggregates may then be degraded by the proteasome or autophagy.

Sign in / Sign up

Export Citation Format

Share Document