[Proteomic analysis associating two-dimensional electrophoresis and mass spectrometry to identify lacrimal proteins: a case study].
OBJECTIVE
Identification of a lacrimal protein by proteomic analysis, i.e., two-dimensional electrophoresis and mass spectrometry.


METHODS
We studied the tears of a 25-year-old female with adrenal gland hyperplasia and hyperandrogenism complaining of chronic dryness and mild bilateral papillary hypertrophy. An allergologic workup was negative. Agarose electrophoresis of the tears showed a bilateral high level of rapid migrated proteins.


RESULTS
Dodecyl sulfate polyacrylamide gel electrophoresis of the tears from both eyes showed a highly stained 15-kDa band after Coomassie colloidal blue coloration compared to controls. On two-dimensional electrophoresis, this band focused on a single spot at pI 7.0. After tryptic digestion in gel, peptide mass fingerprint analysis by matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry provided clear identification of cystatin SN. It is known that mRNA regulated by androgens and encoding glycoproteins homologous to human cystatin exists in the rat lacrimal gland.


CONCLUSIONS
We conclude that the hyperandrogenism of the patient may be cause for the hypersecretion of this cystatin SN, giving an explanation for the high level of rapid migrated proteins (lipocalins). This result provides a concrete example of the proteomic tool used to identify lacrimal proteins, still largely unknown.
Ballot
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Laboratoire de Biologie, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, 28, rue de Charenton, 75571 Paris cedex 12, France.
Marcelo
P
P
Labas
V
V
Doan
S
S
Zamfir
O
O
Chaumeil
C
C
Vinh
J
J
Batellier
L
L
D000328:Adult; D015891:Cystatins / Q000032:analysis*; D015180:Electrophoresis, Gel, Two-Dimensional; D005260:Female; D006801:Humans; D013058:Mass Spectrometry; D040901:Proteomics; D055333:Salivary Cystatins; D013666:Tears / Q000737:chemistry*
C525171:CST1 protein, human; D015891:Cystatins; D055333:Salivary Cystatins