Activin RIB, also known as ALK4, is a glycosylated type I receptor in the superfamily of TGF-β serine/threonine kinase receptors. Activin RIB associates with Activin RIIB to form a receptor complex for activin and inhibin molecules (1). These ligands bind to Activin RIIB which then associates with and phosphorylates the cytoplasmic domain of Activin RIB to initiate signal transduction.Within the ECD, human Activin RIB shares 93% and 95% aa sequence identity with mouse and rat Activin RIB, respectively. It shares 25% - 35% aa sequence identity with other human type I receptors Activin RIA, Activin RIC, BMPR-IA, BMPR-IB, and TGF-β R1. Alternately spliced isoforms of Activin RIB have deletions in the cytoplasmic domain and function as dominant negative inhibitors of activin signaling. Activin receptor signaling is modulated by the direct interaction of Activin RIB with cripto or inhibin binding protein. Activin RIB is excluded from the signaling complex if Activin RIIB first binds inhibin and betaglycan. Activin RIB functions in a wide variety of growth and differentiation processes, including embryonic cell fate and axis determination, cell proliferation and apoptosis, and tumorigenesis.
>90% by SDS-PAGE and analyzed by silver stain.
<0.01EU/µg as determined by the LAL method
Fusion Protein Tag
Fc Fusion Protein
Protein Accession No.
Amino Acid Sequence
llcactscl qanytcetdg acmvsffnld gmehhvrtci pkvelvpagk pfyclssedl rnthccytdy cnridlrvps ghlkepehps mwgpveiegr mdpkscdkth tcppcpapel lggpsvflfp pkpkdtlmis rtpevtcvvv dvshedpevk fnwyvdgvev hnaktkpree qynstyrvvs vltvlhqdwl ngkeykckvs nkalpapiek tiskakgqpr epqvytlpps rdeltknqvs ltclvkgfyp sdiavewesn gqpennyktt ppvldsdgsf flyskltvdk srwqqgnvfs csvmhealhn hytqkslsls pgkhhhhhh
N-terminal Sequence Analysis
State of Matter
Predicted Molecular Mass
The predicted molecular weight of Recombinant Human Activin RIB is Mr 37.5 kDa. However, the actual molecular weight as observed by migration on SDS-PAGE is Mr 45-50 kDa.
This recombinant protein was 0.2 µm filtered and lyophilized from modified Dulbecco’s phosphate buffered saline (1X PBS) pH 7.2 – 7.3 with no calcium, magnesium, or preservatives.
Storage and Stability
This lyophilized protein is stable for six to twelve months when stored desiccated at -20°C to -70°C. After aseptic reconstitution, this protein may be stored at 2°C to 8°C for one month or at -20°C to -70°C in a manual defrost freezer. Avoid Repeated Freeze Thaw Cycles. See Product Insert for exact lot specific storage instructions.
Country of Origin
Next Day Ambient
NCBI Gene Bank
IMPORTANT Use lot specific datasheet for all technical information pertaining to this recombinant protein.
Products are for research use only. Not for use in diagnostic or therapeutic procedures.