Galectin-1 is a

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...

that in humans is encoded by the ''LGALS1''

gene In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...

Gene and protein

LGALS1 contains four

exon An exon is any part of a gene that will form a part of the final mature RNA produced by that gene after introns have been removed by RNA splicing. The term ''exon'' refers to both the DNA sequence within a gene and to the corresponding sequence ...

s. The galectin-1 protein is 135 amino acids in length and highly conserved across species. It can be found in the nucleus, the cytoplasm, the cell surface and in the extracellular space. Galectins in general lack a traditional signal sequence, but are still secreted across the plasma membrane. This non-traditional secretion requires a functional

glycan The terms glycans and polysaccharides are defined by IUPAC as synonyms meaning "compounds consisting of a large number of monosaccharides linked glycosidically". However, in practice the term glycan may also be used to refer to the carbohydrate ...

binding site. Galectin 1 contains a single carbohydrate recognition domain through which it can bind glycans both as a monomer and as a homodimer. Dimers are non-covalently bound and will spontaneously disassociate in low concentration. Galectin 1 does not bind glycans when oxidized. Having 6 cysteine residues, the oxidation state has a significant effect on the protein structure. The oxidized form is reported to have alternative functions not involving carbohydrate binding.

Function

The

galectin Galectins are a class of proteins that bind specifically to β-galactoside sugars, such as ''N''-acetyllactosamine (Galβ1-3GlcNAc or Galβ1-4GlcNAc), which can be bound to proteins by either N-linked or O-linked glycosylation. They are also te ...

s are a family of beta-galactoside-binding proteins implicated in modulating cell-cell and cell-matrix interactions. Galectin-1 may act as an

autocrine Autocrine signaling is a form of cell signaling in which a cell secretes a hormone or chemical messenger (called the autocrine agent) that binds to autocrine receptors on that same cell, leading to changes in the cell. This can be contrasted with ...

negative growth factor that regulates

cell proliferation Cell proliferation is the process by which ''a cell grows and divides to produce two daughter cells''. Cell proliferation leads to an exponential increase in cell number and is therefore a rapid mechanism of tissue growth. Cell proliferation ...

. Galectin-1 expression in Hodgkin Lymphoma has also been shown to mediate immunosuppression of CD8+ T-cells. It has been linked to the inflammatory process in HIV individuals, and some research suggest that Gal-1 could be related to the HIV-1 latency.

Role in pregnancy

Galectin-1 is thought to play a role in creating

immune tolerance in pregnancy Immune tolerance in pregnancy or maternal immune tolerance is the immune tolerance shown towards the fetus and placenta during pregnancy. This tolerance counters the immune response that would normally result in the rejection of something foreign i ...

. Galectin-1 is expressed by the endometrial stromal cells throughout the menstrual cycle, however significantly increases during implantation. Galectin-1 induces the differentiation of

Dendritic cells A dendritic cell (DC) is an antigen-presenting cell (also known as an ''accessory cell'') of the mammalian immune system. A DC's main function is to process antigen material and present it on the cell surface to the T cells of the immune system ...

towards a phenotype which dampens T helper 1 cells and

T helper 17 cell T helper 17 cells (Th17) are a subset of pro-inflammatory T helper cells defined by their production of interleukin 17 (IL-17). They are related to T regulatory cells and the signals that cause Th17s to actually inhibit Treg differentiation. Howe ...

s and dampens inflammation via

interleukin-10 Interleukin 10 (IL-10), also known as human cytokine synthesis inhibitory factor (CSIF), is an anti- inflammatory cytokine. In humans, interleukin 10 is encoded by the ''IL10'' gene. IL-10 signals through a receptor complex consisting of two IL- ...

and interleukin-27. It also plays a role in the formation and expression of

HLA-G HLA-G histocompatibility antigen, class I, G, also known as human leukocyte antigen G (HLA-G), is a protein that in humans is encoded by the ''HLA-G'' gene. HLA-G belongs to the HLA nonclassical class I heavy chain paralogues. Classical HLA I p ...

in the

syncytium A syncytium (; : syncytia; from Greek: σύν ''syn'' "together" and κύτος ''kytos'' "box, i.e. cell") or symplasm is a multinucleate cell that can result from multiple cell fusions of uninuclear cells (i.e., cells with a single nucleus), i ...

Interactions

LGALS1 has been shown to

interact Advocates for Informed Choice, dba interACT or interACT Advocates for Intersex Youth, is a 501(c)(3) nonprofit organization advocating for the legal and human rights of children with intersex traits. The organization was founded in 2006 and fo ...

with

GEMIN4 Gem-associated protein 4 is a protein that in humans is encoded by the ''GEMIN4'' gene. Function The product of this gene is part of the SMN protein complex localized to the cytoplasm, nucleoli, and to discrete nuclear bodies called Gemini ...

HRAS GTPase HRas, from "Harvey Rat sarcoma virus", also known as transforming protein p21 is an enzyme that in humans is encoded by the gene. The ''HRAS'' gene is located on the short (p) arm of chromosome 11 (human), chromosome 11 at position 15.5, ...

Gene and protein

Function

Role in pregnancy

Interactions

See also

References

Further reading