Sphingomyelin Phosphodiesterase 3 (COL4A3BP) Antibody – Rabbit Polyclonal

This gene encodes a kinase that specifically phosphorylates the N-terminal region of the non-collagenous domain of the alpha 3 chain of type IV collagen, known as the Goodpasture antigen. Goodpasture disease is the result of an autoimmune response directed at this antigen. One isoform of this protein is also involved in ceramide intracellular transport. Three transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jul 2008]

Function: Shelters ceramides and diacylglycerol lipids inside its START domain and mediates the intracellular trafficking of ceramides and diacylglycerol lipids in a non-vesicular manner. Ref.3 Ref.11 Ref.16 Ref.17

Subunit structure: Interacts with COL4A3. Interacts with VAPA and VAPB. Interaction with VAPB is less efficient than with VAPA. Ref.10

Subcellular location: Cytoplasm. Golgi apparatus. Endoplasmic reticulum. Note: Preferentially localized to the Golgi apparatus. Ref.3 Ref.10 Ref.16

Tissue specificity: Widely expressed.

Domain: The START domain recognizes ceramides and diacylglycerol lipids, interacts with membranes, and mediates the intermembrane transfer of ceramides and diacylglycerol lipids. Ref.3The PH domain targets the Golgi apparatus. Ref.3The FFAT motif is required for interaction with VAPA and VAPB. Ref.3

Post-translational modification: Phosphorylation on Ser-132 decreases the affinity toward phosphatidylinositol 4-phosphate at Golgi membranes and reduces ceramide transfer activity. Inactivated by hyperphosphorylation of serine residues by CSNK1G2/CK1 that triggers dissociation from the Golgi complex, thus down-regulating ER-to-Golgi transport of ceramide and sphingomyelin synthesis.

Sequence similarities: Contains 1 PH domain.Contains 1 START domain.

Caution: Was originally (Ref.1) reported to have a protein kinase activity and to phosphorylate on Ser and Thr residues the Goodpasture autoantigen (in vitro).