BIP, a BRAM-interacting protein involved in TGF-beta signalling, regulates body length in Caenorhabditis elegans.
BACKGROUND
The TGF-beta superfamily has diverse biological activities and is involved in the early development of animals. We previously identified a novel family member, BMP receptor associated molecule (BRAM), which binds to the intracellular domain of BMP type IA receptor and is involved in the BMP signalling pathway.


RESULTS
To identify novel molecules involved in TGF-beta signalling pathways, we performed yeast two-hybrid screening using BRAM as bait. From a Xenopus cDNA library, we cloned a cDNA encoding 693 amino acids and containing the motif for an oxysterol binding protein (OSBP), which we designated BRAM interacting protein (BIP). We then isolated a BIP homologue from the Caenorhabditis elegans that encodes 733 amino acids and also contains the OSBP-like motif. Immunoprecipitation and Western blotting studies revealed that C. elegans BIP could interact with the C. elegans BRAM homologues BRA-1 and BRA-2. C. elegans BIP was expressed in pharyngeal muscle, hypodermis and several neuronal cells, an expression pattern overlaps with those of BRA-1 and BRA-2. Finally, we found that inhibition of BIP expression in C. elegans by double stranded RNA interference produces a Sma phenotype.


CONCLUSIONS
BIP was isolated using the yeast two-hybrid systems. BIP may function in the TGF-beta pathway and regulate body length in C. elegans.
Sugawara
K
K
Division of Morphogenesis, Department of Developmental Biology, National Institute for Basic Biology, Okazaki 444-8585, Japan.
Morita
K
K
Ueno
N
N
Shibuya
H
H
D048868:Adaptor Proteins, Signal Transducing; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D052004:Bone Morphogenetic Protein Receptors; D017173:Caenorhabditis elegans / Q000235:genetics / Q000254:growth & development*; D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins / Q000302:isolation & purification* / Q000378:metabolism / Q000502:physiology; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D010446:Peptide Fragments / Q000235:genetics / Q000378:metabolism; D011233:Precipitin Tests; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*; D017978:Receptors, Growth Factor; D011987:Receptors, Steroid / Q000737:chemistry; D015398:Signal Transduction; D014018:Tissue Distribution; D016212:Transforming Growth Factor beta / Q000378:metabolism; D020798:Two-Hybrid System Techniques; D014981:Xenopus / Q000235:genetics; D000098825:Oxysterol Binding Proteins
D048868:Adaptor Proteins, Signal Transducing; C430459:BRA-1 protein, C elegans; D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins; D010446:Peptide Fragments; D011956:Receptors, Cell Surface; D017978:Receptors, Growth Factor; D011987:Receptors, Steroid; D016212:Transforming Growth Factor beta; C436742:bra-2 protein, C elegans; D000098825:Oxysterol Binding Proteins; D052004:Bone Morphogenetic Protein Receptors