Signal sequences: more than just greasy peptides

Martoglio, Bruno; Dobberstein, Bernhard

doi:10.1016/s0962-8924(98)01360-9

Cited by 496 publications

(448 citation statements)

References 55 publications

Supporting

Mentioning

431

Contrasting

Unclassified

Order By: Relevance

“…The amino acid sequence and composition of these sites are in agreement with the -3, -1 N-terminal rule of the cleavage site proposed by von Heijne [10,21,22]. For the Leu 22-224 isoform of RS, cleavage occurs with the neutral short side chain Gly at -1 and the uncharged Thr at -3 (Fig-1B).…”

Section: Structural Features Of Rs Signal Sequencesupporting

confidence: 86%

“…The 224 amino acid RS polypeptide consists of a 23 amino acid leader sequence followed by a 39 amino acid RS domain, a highly conserved 157 amino acid discoidin domain and a 5 amino acid Cterminal flanking region. The 23 amino acid leader sequence of RS (Fig-1A) possesses all the structural and functional features associated with eukaryotic signal sequences [10], including a polar (n) region with a net positive charge on its N-terminal side, a central hydrophobic core (h) region and a polar (c) region at C-terminal side with a signal peptidase cleavage site. These structural features of signal sequence serve as a platform on which the signal peptidase and signal recognition particles interact and cleave the 23 amino acid leader peptide from the nascent protein during the translocation of the polypeptide chain into the lumen of the endoplasmic reticulum [11,12].…”

mentioning

confidence: 99%

See 1 more Smart Citation

Identification and characterization of two mature isoforms of retinoschisin in murine retina

Vijayasarathy

Gawinowicz

Zeng

et al. 2006

Biochemical and Biophysical Research Communications

View full text Add to dashboard Cite

Retinoschisin (RS) is a 24 kDa secreted protein expressed in retina and is required for the structural and functional integrity of the retina. RS has been predicted to serve as an adhesive protein but the precise molecular mechanism by which it functions in retina is not yet known. During investigations on structural and functional aspects of RS in murine retina using proteomic tools, we identified two isoforms of RS that differed in mass by 200 Da with no apparent change in charge. Mass spectra and amino acid sequence analysis of the tryptic peptides revealed that these isoforms differed by two amino acids at the N-terminus which suggested processing of RS signal sequence at two cleavage sites by signal peptidase as the basic mechanism underlying the occurrence of two mature RS isoforms in retina. Bioinformatic analysis identified two potential cleavage sites (between amino acids 21-22 and 23-24) in RS signal sequence. The flexibility of the signal peptidase to cleave at two sites is correlated to the amino acid composition of the RS signal sequence. This finding represents a rare example of a naturally occurring signal sequence cleavage at more than one site in vivo. KeywordsRetina; Retinoschisin; Post-Translational Modifications; Isoforms; Signal Sequence; Signal peptidase; Processing; X-linked retinoschisis; Missense mutations Retinoschisin (RS) is a 24 kDa secreted protein expressed in retina and pineal * and is required for the structural and functional integrity of the retina [1]. Based on its conserved discoidin domain sequence, RS is predicted to serve as an adhesion protein in maintaining the organization of the retina [1] but a precise molecular description of RS function is not yet known. Mutations in the RS1 gene that encodes the RS protein cause monogenic X-linked retinoschisis (XLRS) in young males [2][3][4]. Retinoschisis is a form of juvenile macular Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errorsmaybe discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. * Takada et. al.(2006 NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript degeneration in which schisis or splitting within the nuclear and plexiform layers of the retina [5] leads to progressive loss of vision beginning at a young age [6]. Gene therapy is being considered as a therapeutic approach to treat XLRS disease which otherwise has no known cure [7].RS is synthesized in retinal photoreceptor, bipolar amacrine and ganglion cells [8,9]. The 224 amino acid RS polypeptide consists of a 23 amino acid leader sequence followed by a 39 amino acid RS domain, a highly conserved 157 amino acid discoidin domain and a 5 amino acid Ctermin...

show abstract

Section: Structural Features Of Rs Signal Sequencesupporting

confidence: 86%

mentioning

confidence: 99%

Identification and characterization of two mature isoforms of retinoschisin in murine retina

Vijayasarathy

Gawinowicz

Zeng

et al. 2006

Biochemical and Biophysical Research Communications

View full text Add to dashboard Cite

show abstract

“…However, processing by yet other proteolytic systems deliver peptides that are presented in a TAP-independent way. The above-mentioned SP and SPP proteases produce such TAPindependent peptides within the ER and proprotein convertases like PC7 and furin have been shown to facilitate TAP-independent presentation in the secretory route [29][30][31][32]. Interestingly, our preliminary data show that presentation of the Trh4 peptide is independent of these known enzyme systems, indicating that yet other pathways exist.…”

mentioning

confidence: 68%

“…Peptides for which MHC-I binding and stability were analyzed were Trh4 379-387 (MCLRMTAVM), LCMV gp33 [33][34][35][36][37][38][39][40][41][42] [20][21][22][23][24][25][26][27][28] (TNLLNDRVL) and gp100 [25][26][27][28][29][30][31][32][33] (EGSRNQDWL). RMA-S cells were cultured for 2 days at 261C to accumulate peptide receptive MHC-I molecules on the cell surface [60].…”

Section: Peptide Binding and Stability Assaysmentioning

confidence: 99%

“…Biochemical analysis of the peptide repertoire of TAP-deficient T2 cells revealed abundant presentation of signal sequence-derived peptides [25][26][27]. Indeed, signal sequences are liberated by the combined action of signal peptidase (SP) and signal peptide peptidase (SPP) and are directly available for loading into MHC-I [28,29]. A second characterized processing pathway that bypasses TAP is active in the secretory route and is mediated by members of the proprotein convertase (PC) family, like furin [30][31][32].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Peptide transporter TAP mediates between competing antigen sources generating distinct surface MHC class I peptide repertoires

et al. 2011

View full text Add to dashboard Cite

We recently described a category of TAP-independent peptide-epitopes that are selectively presented by cells with processing defects in the classical MHC class I (MHC-I) pathway. Here, we studied the ER-resident ceramide synthase Trh4 as a prototypic example of these neo-antigens and found that moderate inhibition of TAP permits cell surface presentation of the Trh4 peptide. The absence of this peptide from WT cells was not related to the binding or stability of the Trh4/D b complexes, or to the availability of MHC-I heavy chains, but rather to the limited expression of the antigen. Strongly elevated antigen levels were needed to reach comparable peptide display on WT as on TAP-deficient cells. Our data suggest that the normal influx of TAP-transported peptides in the ER during routine processing creates an efficient barrier for peptides from alternative processing routes. Impairment of TAP function, as commonly found in cancers and virus-infected cells, lowers this resistance allowing for MHC-I presentation of other peptide sources.Key words: Antigen processing . Cytotoxic T lymphocytes . Transporter associated with peptide processing Supporting Information available online IntroductionCytotoxic T lymphocytes (CTLs) are key effector cells of the adaptive immune system and circulate throughout the body in search of their cognate peptides that are presented by MHC class I (MHC-I) molecules. T-cell receptors determine the antigen specificity of CTLs and engagement with peptide/MHC-I complexes leads to their activation and elimination of target cells. Therefore, the process of MHC-I antigen processing and presentation, which operates in all nucleated cells of our body, is crucial for CTL immune surveillance [1][2][3]. The highly complex repertoire of MHC-I presented peptides reflects the total proteome of cells and derives from the physiological turnover of proteins, a process that is largely operated by the multicatalytic enzyme proteasome [4,5]. In addition to the proteasome, other proteolytic enzymes in the cytosol have been implicated in the liberation of peptides for MHC-I presentation, some of which can compensate for the lack of proteasome activity [1,6,7]. For instance, tripeptidyl peptidase II (TPPII), insulin-degrading enzyme (IDE), thimet oligopeptidase (TOP) and nardilysin have been implicated in the generation of some CTL epitopes [8][9][10]. However, the relative contributions of these novel peptidases and Ã These authors contributed equally to this work 3114their cooperation with the proteasome have not been fully characterized.The intermediate peptide products are rescued from total breakdown by these cytosolic proteases through translocation into the ER. Subsequently, peptides are trimmed and loaded into the grooves of MHC-I molecules, a dynamic process that is mediated by the peptide loading complex (PLC) consisting of MHC-I, b2m, ERp57, TAP, tapasin and chaperones [11][12][13]. The TAP peptide transport is operated by the heterodimer pump TAP1/TAP2, members of the ABC transporter family. The imp...

show abstract

Design and Use of Fluorescent Fusion Proteins in Cell Biology

2005

View full text Add to dashboard Cite

The discovery that green fluorescent protein (GFP) variants and coral fluorescent proteins can be functionally expressed in heterogeneous systems has revolutionized cell biology (Lippincott-Schwartz et al., 2001; Miyawaki et al., 2003). Unmodified fluorescent proteins (FPs) can be visualized by fluorescence microscopy and can serve as probes of environments within living cells. The addition of targeting and retention sequences to FPs can be exploited to highlight specific cellular organelles and to follow their dynamics. The ability of FPs to fold, even when fused to cellular proteins, has made it possible to directly study the biology of proteins in vivo. A protein of interest can be monitored in cells or even in whole animals without having to purify, label, and deliver the protein into cells. Thus, it is now possible to label and observe proteins in previously inaccessible environments, such as organelle lumena. Fusion of FPs to proteins of interest can reveal a wealth of data, including information on a protein's steady-state distribution, dynamics, history, and association with other proteins (Lippincott-Schwartz et al., 2001; 2003). In this unit, strategies and background for designing and creating fluorescent fusion proteins (FFPs) are described. To design an FFP, the investigator must consider what the FFP's intended use is, which fluorescent tag to add, whether the FP has complicating issues related to the protein of interest's environment (e.g., pH sensitivity, enhanced aggregation), and where to insert the FP. The actual construction of FFPs can be readily accomplished using standard molecular biology techniques and will only be described in general terms in the Basic Protocol. Investigators seeking specific advice on cloning techniques are referred to

show abstract

Signal sequences: more than just greasy peptides

Cited by 496 publications

References 55 publications

Identification and characterization of two mature isoforms of retinoschisin in murine retina

Identification and characterization of two mature isoforms of retinoschisin in murine retina

Peptide transporter TAP mediates between competing antigen sources generating distinct surface MHC class I peptide repertoires

Design and Use of Fluorescent Fusion Proteins in Cell Biology

Contact Info

Product

Resources

About