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beta-2-syntrophin; 59 kD dystrophin-associated protein A1 basic component 2; syntrophin-3; SNT3; syntrophin-like; SNTL (SNTB2 D16S2531E SNT2B2 SNTL)

Function: - adapter protein - binds to & probably organizes the subcellular localization of a variety of membrane proteins - may link various receptors to the actin cytoskeleton & the dystrophin glycoprotein complex - may play a role in regulation of secretory granules via its interaction with PTPRN - phosphorylated; partially dephosphorylated upon insulin stimulation - interacts with other members of the syntrophin family: SNTA1 & SNTB1; & with the Na+ channel proteins SCN4A & SCN5A - interacts with SAST, MAST205, microtubules & microtubule-associated proteins - interacts with the dystrophin protein DMD & related proteins DTNA & UTRN, & with the neuroregulin receptor ERBB4 - interacts with PTPRN when phosphorylated, protecting PTPRN from protein cleavage by CAPN1 - dephosphorylation upon insulin stimulation disrupts interaction with PTPRN & results in cleavage of PTPRN Structure: - monomer & homodimer (probable) - the 1st PH domain mediates oligomerization (Ca+2 dependent) (putative) - the PDZ domain binds to the last 3 or 4 amino acids of ion channels & receptor proteins; association with dystrophin or related proteins probably leaves the PDZ domain available to recruit proteins to the membrane (putative) - the SU domain binds calmodulin (Ca+2-dependent) (putative) - belongs to the syntrophin family - contains 1 PDZ domain (DHR domain) - contains 2 PH domains - contains 1 SU domain (syntrophin unique) Compartment: - membrane, cytoplasmic vesicle, secretory vesicle membrane - peripheral membrane protein - cell junction - cytoplasm, cytoskeleton - in muscle, localized at the neuromuscular junction - in insulinoma cell line, it is enriched in secretory granules Alternative splicing: named isoforms=2 Expression: - ubiquitous - isoform 1 is the predominant isoform - isoform 2 is highly expressed in liver & heart - low expression of isoform 2 in all other tissues Notes: - one isoform may lack domains required for interaction with dystrophin related proteins - one isoforma may be produced at very low levels due to a premature stop codon in the mRNA, leading to nonsense-mediated mRNA decay

General

phosphoprotein syntrophin (dystrophin-associated protein)

Properties

SIZE: entity length = 540 aa MW = 58 kD COMPARTMENT: cytoplasm MOTIF: alanine-rich region {54-57} MOTIF: alanine residue (SEVERAL) alanine-rich region {66-69} MOTIF: alanine residue (SEVERAL) Ser phosphorylation site {S95} Ser phosphorylation site {S110} PDZ domain NAME: PDZ domain SITE: 115-198 PH domain {163-300} MOTIF: Thr phosphorylation site {T201} Ser phosphorylation site {S222} Ser phosphorylation site {S233} PH domain {325-437} MOTIF: Ser phosphorylation site {S393} SU {484-540} MOTIF: binding site SITE: 518-540 FOR-BINDING-OF: calmodulin

Database Correlations

OMIM 600027 UniProt Q13425 PFAM correlations Entrez Gene 6645 Kegg hsa:6645

References

  1. OMIM :accession 600027
  2. Entrez Gene :accession 6645
  3. UniProt :accession Q13425