BRAM1, a BMP receptor-associated molecule involved in BMP signalling.
BACKGROUND
TGF-beta superfamily members elicit signals through the stimulation of serine/threonine-kinase receptors. Recently, molecules associated with several TGF-beta family receptors have been cloned. One such molecule, the immunophilin FKBP12, has been reported to interact with TGF-beta family type I receptors. However, the identity of signalling specific molecules interacting with the receptor was unknown.


RESULTS
To clarify the factors mediating bone morphogenetic protein (BMP) receptor signalling, a cytoplasmic molecule associated with the BMP type IA receptor (BMPR-IA) was isolated using the yeast two-hybrid system. We designated the molecule BMP receptor associated molecule 1 (BRAM1). BRAM1 is an alternatively spliced form of BS69, a factor previously identified as an adenovirus E1A-associated protein. BRAM1 was localized to the cytoplasmic region in mammalian cells, whereas BS69 is localized to the nucleus. BRAM1 bound specifically to BMPR-IA in mammalian cells. The C-terminal half of BRAM1 was found to be sufficient for binding to BMPR-IA.


CONCLUSIONS
BRAM1, a BMPR-IA associated molecule, was isolated using the yeast two-hybrid system, and found to associate specifically with BMPR-IA. BRAM1 may thus serve as an interacting protein in the BMP signal pathway.
Kurozumi
K
K
Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan.
Nishita
M
M
Yamaguchi
K
K
Fujita
T
T
Ueno
N
N
Shibuya
H
H
D048868:Adaptor Proteins, Signal Transducing; D017398:Alternative Splicing; D052005:Bone Morphogenetic Protein Receptors, Type I; D019485:Bone Morphogenetic Proteins / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002451:Cell Compartmentation; D018797:Cell Cycle Proteins; D003001:Cloning, Molecular; D056970:Co-Repressor Proteins; D018076:DNA, Complementary / Q000235:genetics; D004268:DNA-Binding Proteins; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D010446:Peptide Fragments / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D017978:Receptors, Growth Factor / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics; D015398:Signal Transduction; D014018:Tissue Distribution; D016212:Transforming Growth Factor beta / Q000378:metabolism
D048868:Adaptor Proteins, Signal Transducing; D019485:Bone Morphogenetic Proteins; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D056970:Co-Repressor Proteins; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; D010446:Peptide Fragments; D017978:Receptors, Growth Factor; C099510:TAB1 protein, MAPKKK activator, vertebrate; C486300:TAB1 protein, human; D016212:Transforming Growth Factor beta; C094763:ZMYND11 protein, human; D017346:Protein Serine-Threonine Kinases; C498211:BMPR1A protein, human; D052005:Bone Morphogenetic Protein Receptors, Type I