Giantin or Golgin subfamily B member 1 is a

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...

that in humans is encoded by the ''GOLGB1''

gene In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...

. Giantin is located at the cis-medial rims of the Golgi apparatus and is part of the Golgi matrix that is responsible for membrane trafficking in secretory pathway of proteins. This function is key for proper localisation of proteins at the

plasma membrane The cell membrane (also known as the plasma membrane (PM) or cytoplasmic membrane, and historically referred to as the plasmalemma) is a biological membrane that separates and protects the interior of all cells from the outside environment (t ...

and outside the cell (extracellular region) which is important for cell function that is dependent on for example

receptor Receptor may refer to: * Sensory receptor, in physiology, any structure which, on receiving environmental stimuli, produces an informative nerve impulse *Receptor (biochemistry), in biochemistry, a protein molecule that receives and responds to a ...

s and the

extracellular matrix In biology, the extracellular matrix (ECM), also called intercellular matrix, is a three-dimensional network consisting of extracellular macromolecules and minerals, such as collagen, enzymes, glycoproteins and hydroxyapatite that provide stru ...

function. Recent animal model knockout studies of ''GOLGB1'' in

mice A mouse ( : mice) is a small rodent. Characteristically, mice are known to have a pointed snout, small rounded ears, a body-length scaly tail, and a high breeding rate. The best known mouse species is the common house mouse (''Mus musculus' ...

rat Rats are various medium-sized, long-tailed rodents. Species of rats are found throughout the order Rodentia, but stereotypical rats are found in the genus ''Rattus''. Other rat genera include ''Neotoma'' ( pack rats), ''Bandicota'' (bandicoot ...

, and

zebrafish The zebrafish (''Danio rerio'') is a freshwater fish belonging to the minnow family ( Cyprinidae) of the order Cypriniformes. Native to South Asia, it is a popular aquarium fish, frequently sold under the trade name zebra danio (and thus often ...

have shown that phenotypes are different between species ranging from mild to severe craniofacial defects in the rodent models to just minor size defects in zebrafish. However, in adult zebrafish a

tumoral calcinosis Tumoral calcinosis is a rare condition in which there is calcium deposition in the soft tissue in periarticular location, around joints, outside the joint capsule. They are frequently (0.5–3%) seen in patients undergoing renal dialysis. Clinica ...

-like phenotype was observed, and in humans such phenotype has been linked to defective glycosyltransferase function (e.g.

GALNT3 Polypeptide N-acetylgalactosaminyltransferase 3 is an enzyme that in humans is encoded by the ''GALNT3'' gene. This gene encodes UDP-GalNAc transferase 3, a member of the polypeptide GalNAc transferase (GalNAc-T) family. This family transfers an ...

protein).

Function and Interactions

Giantin is a disulfide-linked homodimer which contains several (around 37) coiled-coiled domains. GOLGB1 protein has been shown to

interact Advocates for Informed Choice, dba interACT or interACT Advocates for Intersex Youth, is a 501(c)(3) nonprofit organization using innovative strategies to advocate for the legal and human rights of children with intersex traits. The organizati ...

with ACBD3 and with

PLK3 Polo-like kinase 3 (Drosophila), also known as PLK3, is an enzyme which in humans is encoded by the ''PLK3'' gene. Function Cytokine-inducible kinase is a putative serine/threonine kinase. CNK contains both a catalytic domain and a putative r ...

and vesicle tethering small GTPases Rab1 and Rab6. Giantin also interacts with P115 at the N-terminal coils facilitating binding to the other Golgi matrix protein GM130 that is thought to be important for Golgi secretory function. Loss-of function studies of giantin have also suggested a role in

primary cilia The cilium, plural cilia (), is a membrane-bound organelle found on most types of eukaryotic cell, and certain microorganisms known as ciliates. Cilia are absent in bacteria and archaea. The cilium has the shape of a slender threadlike projecti ...

function and defective regulation of glycosyltransferase expression and calcineurin signalling in tissue culture cells.

Function and Interactions

References

Further reading