Related Experiment Video
Updated: Jun 12, 2026
09:04
Optimizing Tear Collection in Mice for mRNA and Protein Analysis
Published on: July 19, 2024
Post-translation modification of proteins in tears
Jingjing You1, Anna Fitzgerald, Paul J Cozzi
1Minomic International Ltd, NSW, Australia.
Electrophoresis
|May 28, 2010
Summary
This study maps tear protein modifications using sequential dyes, revealing novel antimicrobial protein dermcidin and confirming glycosylated lipocalin 1 and cystatin S. These findings advance understanding of tear protein profiles and potential biomarkers.
Area of Science:
- Proteomics
- Biochemistry
- Immunology
Background:
- Tear proteins play crucial roles in ocular surface defense and homeostasis.
- Understanding post-translational modifications (PTMs) of tear proteins is vital for identifying disease biomarkers.
- Previous tear proteomic studies have limitations in comprehensively analyzing PTMs.
Purpose of the Study:
- To develop and apply a novel 2-DE method using sequential fluorescent dyes for simultaneous analysis of phosphoproteome, glycoproteome, and total proteome in human tears.
- To create a comprehensive map of PTM profiles in tear proteins.
- To identify novel tear proteins and characterize known proteins with specific PTMs.
Main Methods:
- Utilized two-dimensional electrophoresis (2-DE) with sequential staining: Pro-Q Diamond for phosphoproteins, Pro-Q Emerald for glycoproteins, and Sypro Ruby for total proteins.
- Minimized gel-to-gel variations for accurate comparative analysis of different protein profiles.
- Identified proteins using mass spectrometry (implied, though not explicitly stated in abstract).
Main Results:
- Successfully mapped phosphoprotein, glycoprotein, and total protein profiles of human tears.
- Identified dermcidin, a novel antimicrobial protein, in tear fluid, suggesting a new role in ocular defense.
- Provided the first experimental evidence for glycosylated lipocalin 1 and cystatin S in tears.
- Detected Nucleobindin 2 exclusively via phosphoprotein staining, indicating phosphorylation in the tear environment.
Conclusions:
- The sequential dye approach is effective for comprehensive tear protein PTM analysis and biomarker discovery.
- The identification of dermcidin expands our understanding of the innate immune system in tears.
- This study lays the foundation for future research into tear protein PTMs and their clinical relevance.
Related Concept Videos
01:31Translation
Lesson: Translation
Translation is the process of synthesizing proteins from the genetic information carried by messenger RNA (mRNA). Following transcription, it constitutes the final step in the expression of genes. This process is carried out by ribosomes, complexes of protein and specialized RNA molecules. Ribosomes, transfer RNA (tRNA), and other proteins produce a chain of amino acids—the polypeptide—as the end product of translation.
Translation Produces the Building Blocks of Life
Translation is the process of synthesizing proteins from the genetic information carried by messenger RNA (mRNA). Following transcription, it constitutes the final step in the expression of genes. This process is carried out by ribosomes, complexes of protein and specialized RNA molecules. Ribosomes, transfer RNA (tRNA), and other proteins produce a chain of amino acids—the polypeptide—as the end product of translation.
Translation Produces the Building Blocks of Life
01:31Translation
Lesson: Translation
Translation is the process of synthesizing proteins from the genetic information carried by messenger RNA (mRNA). Following transcription, it constitutes the final step in the expression of genes. This process is carried out by ribosomes, complexes of protein and specialized RNA molecules. Ribosomes, transfer RNA (tRNA), and other proteins produce a chain of amino acids—the polypeptide—as the end product of translation.
Translation Produces the Building Blocks of Life
Translation is the process of synthesizing proteins from the genetic information carried by messenger RNA (mRNA). Following transcription, it constitutes the final step in the expression of genes. This process is carried out by ribosomes, complexes of protein and specialized RNA molecules. Ribosomes, transfer RNA (tRNA), and other proteins produce a chain of amino acids—the polypeptide—as the end product of translation.
Translation Produces the Building Blocks of Life
01:26Protein Modifications in the RER
Modification of secretory and transmembrane proteins entering the rough ER begins in the ER lumen. These modifications aid in protein folding and stabilize the acquired tertiary structure. Protein modifications in the rough ER co-occur at different stages of protein folding.
Broadly, these modifications can be categorized into four main categories — glycosylation, formation of disulfide bonds, assembly of protein subunits, and specific proteolytic cleavages like removal of signal sequences.
Broadly, these modifications can be categorized into four main categories — glycosylation, formation of disulfide bonds, assembly of protein subunits, and specific proteolytic cleavages like removal of signal sequences.
02:11Proteins: From Genes to Degradation
Within a biological system, the DNA encodes the RNA, and the nucleotide sequence in the RNA further defines the amino acid sequence in the protein. This is referred to as “The Central Dogma of Molecular Biology” - a term coined by Francis Crick. Central dogma is a firm principle in biology that defines the flow of genetic information within any life form. The two fundamental steps in central dogma are - transcription and translation.
Transcription is the synthesis of RNA molecules by RNA...
Transcription is the synthesis of RNA molecules by RNA...
02:11Proteins: From Genes to Degradation
Within a biological system, the DNA encodes the RNA, and the nucleotide sequence in the RNA further defines the amino acid sequence in the protein. This is referred to as “The Central Dogma of Molecular Biology” - a term coined by Francis Crick. Central dogma is a firm principle in biology that defines the flow of genetic information within any life form. The two fundamental steps in central dogma are - transcription and translation.
Transcription is the synthesis of RNA molecules by RNA...
Transcription is the synthesis of RNA molecules by RNA...
01:26Bacterial Protein Maturation
Bacterial protein maturation is a tightly regulated process that ensures newly synthesized polypeptides achieve correct functional conformations. This maturation involves a series of modifications, folding events, and quality control steps, often assisted by specialized chaperone proteins.N-Terminal ModificationsThe maturation of bacterial polypeptides begins cotranslationally as the polypeptide exits the ribosome. The first amino acid, N-formylmethionine (fMet), is typically modified at the...