Isolation of Galectin-1 from Human Platelets: Its Interaction with Actin

Abstract

Galectins are a family of animal lectins defined by their β-galactoside-binding specificity and a consensus sequence in their carbohydrate-recognition domain. Galectin-1 (Gal-1) is expressed as a non-covalently linked homodimer present in a variety of tissues. Here we describe its isolation from human platelets by a procedure involving ionic exchange chromatography and affinity chromatography on lactose-agarose. Platelet Gal-1 co-purifies with actin, forming an actin-Gal-1 complex which does no dissociate even after treatment with sodium dodecyl sulfate. The presence of both proteins was confirmed by Western blot and by trypsin digestion followed by mass spectrometry identification. By hemagglutination assays we studied the response of recombinant Gal-1/actin, mixed and pre-incubated in different proportions, and then tested against neuraminidase treated rabbit red blood cells. The complex formation was confirmed by confocal microscopy, showing that both proteins co-localised in resting platelets as well as in thrombin-activated ones. These results suggest that endogenous Gal-1 forms an intracellular complex with monomeric actin and that, after platelet activation, Gal-1 could play a role in the polymerization-depolymerization process of actin, which concludes in platelet aggregation.

Expression and functions of galectin-7 in ovarian cancer

“…They had also found that gal-7 was localized in the podosomes of these cells, indicating that gal-7 is involved in organization of the actin cytoskeleton. Such a role has been well documented for galectin-1, which binds to the actin cytoskeleton and participates in actin polymerization-depolymerization by modulating the activity of small GTPase [ 22 , 23 ]. Alternatively, release of gal-7 in the tumor microenvironment by EOC cells may favor establishment of a local immunosuppressive response by killing immune cells.…”

The interplay of galectins-1, -3, and -9 in the immune-inflammatory response underlying cardiovascular and metabolic disease

“…Gal-1 is expressed on the extracellular surface of human platelets [ 121 ]. Gonzalez et al reported that Gal-1 forms complexes with monomeric actin intracellularly and co-purifies with actin in human platelets [ 122 ]. ADP-induced platelet aggregation can be inhibited by lactose or anti-Gal-1 serum in vitro [ 121 ].…”

The Emerging Role of Galectins and O-GlcNAc Homeostasis in Processes of Cellular Differentiation

“…Galectin-1 is expressed in different types of muscle tissues [ 98 ] and essential for muscle functioning due to its association with sarcomeric actin on I bands [ 99 ] and overall high binding affinity to cytoplasmic actin [ 100 ]. Many processes of muscle development are associated with elevated levels of galectin-1 leading to myoblast fusion, terminal differentiation, and muscle regeneration [ 24 , 76 , 77 , 101 ].…”