Leucine-rich Repeat Transmembrane Protein 4, Recombinant Human (LRRTM4)

LRRTM4 (Leucinerich repeat transmembrane protein 4) is a member of the LRRTM family of \nmolecules (1). All LRRTMs are type I transmembrane proteins that contain multiple leucine\nrich repeats, one PDZ consensus cytoplasmic binding domain, and show expression somewhere in the central nervous system. The LRRTM family is iterated across vertebrate (but not invertebrate) species. Human LRRTM4 is synthesized as a 590 amino acid (aa) precursor that contains a 30 aa signal sequence plus a 560 aa mature region. The mature molecule contains a 394 aa extracellular domain (aa 31 424), a 21 aa transmembrane segment, and a 105 aa cytoplasmic region (1, 2). The extracellular domain is characterized by the presence of ten Leurich repeats, flanked by two cysteinerich flanking sequences. Based on other LRRTMs, eukaryotic expression of LRRTM4 will likely yield an 82 86kD glycosylated molecule (3, 4). There are at least two splice variants. Both show a Val substitution for aa 518 590, one of\nwhich is also coupled to an alternative start site at Met312 (5, 6). Mature human LRRTM4 is 95% aa identical to mouse LRRTM4 (1). LRRTM4 is widely expressed, occurring in embryonic distal limb bud mesenchyme plus anterior sclerotome, and in adult testis, lung, muscle and prostate (1, 7). All LRRTMs are also found in brain. LRRTM4 has been identified in adult granular and mitral neurons of the olfactory bulb, neurons of cerebral cortex layers 2, 4, 5 and 6, and on neurons of the dentate gyrus (1). Functionally, it appears that LRRTM4 is involved in both preand postsynaptic modeling. Although embedded in the postsynaptic membrane, LRRTM4\nseems to induce excitatory/glutamatergic presynaptic differentiation. Postsynaptically, LRRTM4 likely facilitates excitatory synapse formation on dendrites, acting in conjunction with multiple ligandreceptor combinations. In particular, the NR1 NMDA subunit has been shown to coalesce,\nor aggregate, in regions that experience LRRTM4 clustering (3, 8).\n\nSource: \nRecombinant corresponding to Gln31-Lys424 from human LRRTM4, C-terminal, 6-His tag, expressed in NSO cells.\n\nMolecular Weight: \n~46kD\n\nBiological Activity:\nMeasured by its binding ability in a functional ELISA. When recombinant, human LRRTM4 is coated at 5ug/ml (100ul/well), recombinant, human Neurexin 1B/Fc Chimera binds with an apparent KD<15nM.\n \nEndotoxin Level:\n<1EU/ug (LAL method)\n\nStorage and Stability:\nLyophilized powder may be stored at -20 degrees C. Stable for 12 months at -20 degrees C. Reconstitute with sterile buffer. Aliquot to avoid repeated freezing and thawing. Store at -20 degrees C. Reconstituted product is stable for 6 months at -20 degrees 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.

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SPECIFICATIONS

Catalog Number

L2020-76

Size

50ug

Form

Supplied as a lyophilized powder from PBS. Reconstitute with sterile PBS to a concentration of 0.3mg/ml.

Purity

~95% (SDS-PAGE)

References

1. Lauren, J. et al. (2003) Genomics 81:411. 2. SwissProt # Q86VH4. 3. Linhoff, M.W. et al. (2009) Neuron 61:734. 4. Majercak, J. et al. (2006) Proc. Natl. Acad. Sci. USA 103:17967. 5. GenBank Accession # EAW99585. 6. GenBank Accession # AAH17769. 7. Haines, B.P. & P. Rigby (2007) Gene Expr. Patterns 7:23. 8. Brose, N. (2009) Neuron 61:650.