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DAG1 phospho Y892

Function

The dystroglycan complex is involved in a number of processes including laminin and basement membrane assembly, sarcolemmal stability, cell survival, peripheral nerve myelination, nodal structure, cell migration, and epithelial polarization.

Alpha-dystroglycan

Extracellular peripheral glycoprotein that acts as a receptor for extracellular matrix proteins containing laminin-G domains. Receptor for laminin-2 (LAMA2) and agrin in peripheral nerve Schwann cells. Also acts as a receptor for laminin LAMA5 (By similarity).

Beta-dystroglycan

Transmembrane protein that plays important roles in connecting the extracellular matrix to the cytoskeleton. Acts as a cell adhesion receptor in both muscle and non-muscle tissues. Receptor for both DMD and UTRN and, through these interactions, scaffolds axin to the cytoskeleton. Also functions in cell adhesion-mediated signaling and implicated in cell polarity.

Alpha-dystroglycan

(Microbial infection) Acts as a receptor for lassa virus and lymphocytic choriomeningitis virus glycoprotein and class C new-world arenaviruses (PubMed:16254364, PubMed:19324387, PubMed:17360738). Acts as a Schwann cell receptor for Mycobacterium leprae, the causative organism of leprosy, but only in the presence of the G-domain of LAMA2 (PubMed:9851927).

Involvement in disease

Muscular dystrophy-dystroglycanopathy limb-girdle C9

MDDGC9

An autosomal recessive muscular dystrophy showing onset in early childhood, and associated with mental retardation without structural brain anomalies.

None

The disease is caused by variants affecting the gene represented in this entry. MDDGC7 is caused by DAG1 mutations that interfere with normal post-translational processing, resulting in defective DAG1 glycosylation and impaired interactions with extracellular-matrix components. Other muscular dystrophy-dystroglycanopathies are caused by defects in enzymes involved in protein O-glycosylation.

Muscular dystrophy-dystroglycanopathy congenital with brain and eye anomalies A9

MDDGA9

An autosomal recessive disorder characterized by congenital muscular dystrophy associated with cobblestone lissencephaly and other brain anomalies, eye malformations, profound mental retardation, and death usually in the first years of life. Included diseases are the more severe Walker-Warburg syndrome and the slightly less severe muscle-eye-brain disease.

None

The disease is caused by variants affecting the gene represented in this entry.

Post-translational modifications

Alpha-dystroglycan

O-glycosylated. POMGNT1 catalyzes the initial addition of N-acetylglucosamine, giving rise to the GlcNAc(beta1-2)Man(alpha1-)O-Ser/Thr moiety and thus providing the necessary basis for the addition of further carbohydrate moieties (PubMed:27493216). Heavily O-glycosylated comprising of up to two thirds of its mass and the carbohydrate composition differs depending on tissue type. Mucin-type O-glycosylation is important for ligand binding activity. O-mannosylation is found in high abundance in both brain and muscle where the most abundant glycan is Sia-alpha-2-3-Gal-beta-1-4-Glc-NAc-beta-1-2-Man. In muscle, glycosylation on Thr-317, Thr-319 and Thr-379 by a phosphorylated O-mannosyl glycan with the structure 2-(N-acetylamido)-2-deoxygalactosyl-beta-1,3-2-(N-acetylamido)-2-deoxyglucosyl-beta-1,4-6-phosphomannose is mediated by like-acetylglucosaminyltransferase (LARGE1) protein and is required for laminin binding (PubMed:20044576, PubMed:21987822, PubMed:24256719). The O-glycosyl hexose on Thr-367, Thr-369, Thr-372, Thr-381 and Thr-388 is probably mannose. O-glycosylated in the N-terminal region with a core 1 or possibly core 8 glycan. The brain form displays a unique glycosylation pattern which is absent in other tissues; this form shows enhanced binding to laminin LAMA5 compared to the skeletal muscle form (By similarity).

Alpha-dystroglycan

(Microbial infection) O-mannosylation is required for binding lymphocytic choriomeningitis virus, Old World Lassa fever virus, and clade C New World arenaviruses.

Beta-dystroglycan

N-glycosylated.

Autolytic cleavage produces the alpha and beta subunits. In cutaneous cells, as well as in certain pathological conditions, shedding of beta-dystroglycan can occur releasing a peptide of about 30 kDa.

SRC-mediated phosphorylation of the PPXY motif of the beta subunit recruits SH2 domain-containing proteins, but inhibits binding to WWW domain-containing proteins, DMD and UTRN. This phosphorylation also inhibits nuclear entry.

Tissue specificity

Expressed in a variety of fetal and adult tissues. In epidermal tissue, located to the basement membrane. Also expressed in keratinocytes and fibroblasts.

Cellular localization

  • Alpha-dystroglycan
  • Secreted
  • Extracellular space
  • Beta-dystroglycan
  • Cell membrane
  • Single-pass type I membrane protein
  • Cytoplasm
  • Cytoskeleton
  • Nucleus
  • Nucleoplasm
  • Cell membrane
  • Sarcolemma
  • Cell junction
  • Synapse
  • Postsynaptic cell membrane
  • The monomeric form translocates to the nucleus via the action of importins and depends on RAN. Nuclear transport is inhibited by Tyr-892 phosphorylation. In skeletal muscle, this phosphorylated form locates to a vesicular internal membrane compartment. In muscle cells, sarcolemma localization requires the presence of ANK2, while localization to costameres requires the presence of ANK3. Localizes to neuromuscular junctions (NMJs) in the presence of ANK2 (By similarity). In peripheral nerves, localizes to the Schwann cell membrane. Colocalizes with ERM proteins in Schwann-cell microvilli.

Alternative names

  • Dystroglycan
  • Dystrophin-associated glycoprotein 1
  • DAG1

Target type

Proteins

Primary research area

Neuroscience

Molecular weight

97441Da