Synthesis, isolation, and characterization of endogenous .beta.-galactoside-binding lectins in human leukocytes

Abstract

Galaptin, a beta-galactoside-binding lectin, was isolated from human buffy coat cells (peripheral leukocytes) and spleen by affinity chromatography. The molecular weight (32K) of the native buffy coat galaptin was similar to that for splenic galaptin. Their subunit molecular weight (14.5K), pI (4.60-4.85), and amino acid composition were identical. Both galaptins showed the presence of a single polypeptide when subjected to reversed-phase HPLC. Monospecific rabbit polyclonal antiserum raised against the 14.5-kDa subunit of splenic galaptin reacted with a 14.5-kDa polypeptide present in buffy coat cells, Epstein-Barr virus-immortalized B lymphoblastoid cells, and HL-60 promyelocytic leukemia cells. However, galaptin was not synthesized in vitro by buffy coat cells. Rather, a monomeric beta-galactoside-binding protein of Mr 15.5-16.5K that is immunologically distinct from galaptin was synthesized. This galactoside-binding protein was separable from galaptin by polyacrylamide gel electrophoresis and by anion-exchange chromatography. In contrast, immunoprecipitation experiments confirmed that galaptin was synthesized by the B lymphoblastoid cells. cDNA corresponding to the B lymphoblastoid cell mRNA encoding galaptin was amplified by the polymerase chain reaction. The amplified product was partially sequenced, and 299 nucleotides were identified. The derived amino acids corresponded to residues 6-65, 84-114, and 118-126 found to be present in human splenic galaptin. Immunohistochemical analyses revealed that galaptin was distributed throughout the cytoplasm of B lymphoblastoid cells rather than being localized to the cell surface.(ABSTRACT TRUNCATED AT 250 WORDS)

Interaction of human neutrophils with endothelial cells regulates the expression of endogenous proteins annexin 1, galectin‐1 and galectin‐3

“…Despite the recently highlighted similarities between the annexin and galectin families , few investigations have analyzed the pattern of expression of endogenous Gal-1 and Gal-3 in human neutrophils (Allen et al, 1991;Truong et al, 1993). In our hand, human resting neutrophils were positive for Gal-1 and Gal-3 immunoreactivity through the nucleus, cytoplasm and plasma membrane as well as detected for ANXA1.…”

Identification of different galectins by immunoblotting after two‐dimensional polyacrylamide gel electrophoresis with immobilized pH gradients

“…Electrophoresis 1996, 17, 600-606 ously described by Allen's group [24], but neither the PIS of the CBPs from leukocytes nor their complete sequences have been published yet.…”

Galectin-1β, a natural monomeric form of galectin-1 lacking its six amino-terminal residues promotes axonal regeneration but not cell death

“…Galectin-1 is expressed in many tissues including skeletal muscle, liver, spleen, and lung. [9][10][11][12][13][14] It has been documented that galectin-1 is a multifunctional molecule involved in the regulation of either cell-cell 15 or cellextracellular matrix adhesion, 16 cell proliferation, 7,17 programmed cell death, 18,19 the Ras signaling pathway, 20,21 and is also related to the mRNA splicing mechanism. 22,23 The amino-terminal alanine residue of Gal-1a is acetylated after the removal of the first methionine residue ( Figure 1a) 24 and Gal-1a forms a homodimer in physiological conditions (Figure 1b).…”