Anti-Kremen (Kremen protein 1, Kringle-containing Protein Marking The Eye And The Nose, Kringle Doma

Kremen (Kringle-containing protein marking the eye and the nose) proteins are type I transmembrane proteins that contain extracellular kringle, WSC and CUB domains and an intracellular region without any conserved motifs (1). Two related members, Kremen-1 and -2, have been identified. Kremens bind a subset of the secreted Dickkopf (Dkk) proteins (Dkk-1, -2 and -4) with high affinity to modulate the canonical Wnt signaling pathway that is transduced by the ternary receptor complex composed of Wnt, the seven-transmembrane domain receptor Frizzled, and the LDL-receptor-related protein 5/6 (LRP5/6) co-receptor (2, 3). Within the Dkk family, Dkk-1 and -4 bind directly to the LRP5/6 co-receptor to antagonize the canonical Wnt/b-catenin signaling pathway, but not the planar cell polarity (PCP) signaling pathway that does not involve LRP5/6 (4). In contrast, Dkk-3 has no effect on Wnt signaling and Dkk-2 can function either as an LRP agonist or antagonist, depending on whether the cell expresses Kremen (5). Kremen co-operates with Dkk to antagonize Wnt signaling via formation of a Kremen-Dkk-LRP ternary complex that triggers the internalization and clearance of the complex from the cell surface (3). All three extracellular domains but not the cytoplasmic region of a membrane anchored Kremen are needed for binding to the second cysteine-rich domain of Dkks (3). Mouse Kremen-1 cDNA encodes a 473aa glycosylated protein with a putative 19aa signal peptide, a 372aa extracellular domain, a 21aa transmembrane domain and a 60aa cytoplasmic domain. In the extracellular domain, it shares 92%, 41% aa sequence identity with human Kremen-1 and mouse Kremen-2, respectively. Mouse Kremen-1 is widely expressed in diverse embryonic (apical ectodermal ridge of the developing fore- and hindlimb buds, telencephalon and the first brachial arch, myotome and sensory tissues) and adult (lung, heart, kidney, skeletal muscle and testis) tissues (1). Applications: Suitable for use in ELISA. Other applications not tested. Recommended Dilution: ELISA: 0.1-0.4ug/ml, ELISA (capture): 2-8ug/ml, Optimal dilutions to be determined by the researcher. Storage and Stability: Lyophilized powder may be stored at -20°C. Stable for 12 months at -20°C. Reconstitute with PBS. Aliquot to avoid repeated freezing and thawing. Store at -20°C. Reconstituted product is stable for 12 months at -20°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.