Isolation of galectin-1 from human platelets: its interaction with actin.

GONZÁLEZ, MARIANA; YOSHIZAKI, LUCILA; WOLFENSTEIN, CARLOTA; FINK, NILDA

PROTEIN JOURNAL

SPRINGER

Lugar: Dordrecht; Año: 2012 vol. 31 p. 8 - 14

1572-3887

Abstract Galectins are a family of animal lectins definedby their b-galactoside-binding specificity and a consensussequence in their carbohydrate-recognition domain.Galectin-1 (Gal-1) is expressed as a non-covalently linkedhomodimer present in a variety of tissues. Here we describeits isolation from human platelets by a procedure involvingionic exchange chromatography and affinity chromatographyon lactose-agarose. Platelet Gal-1 co-purifies withactin, forming an actin-Gal-1 complex which does nodissociate even after treatment with sodium dodecyl sulfate.The presence of both proteins was confirmed byWestern blot and by trypsin digestion followed by massspectrometry identification. By hemagglutination assayswe studied the response of recombinant Gal-1/actin, mixedand pre-incubated in different proportions, and then testedagainst neuraminidase treated rabbit red blood cells. Thecomplex formation was confirmed by confocal microscopy,showing that both proteins co-localised in resting plateletsas well as in thrombin-activated ones. These results suggestthat endogenous Gal-1 forms an intracellular complex withmonomeric actin and that, after platelet activation, Gal-1could play a role in the polymerization-depolymerizationprocess of actin, which concludes in platelet aggregation