Biochem/physiol Actions

APRIL (a proliferation-inducing ligand) functions as a ligand for TACI (transmembrane activator and CAML interactor) and BCMA (B-cell maturation antigen) receptors. It moderately facilitates the proliferation of Jurkat T cells, NIH-3T3 fibroblasts, HT-29 colon carcinoma cells, and A549 lung epithelial cells, though these cells lack TACI or BCMA receptors. Studies in mice show that there is an increase in APRIL and BCMA expression post-SCI (spinal cord injury), which contributes to fibrotic scar formation, an outcome of macrophage and B cell infiltration at the injury site. APRIL KO (knockout) mice show decreased fibrotic scar formation and enhanced axon growth.

General description

APRIL, a member of the TNF superfamily, is expressed in monocytes, macrophages, certain transformed cell lines, certain cancers of colon, and lymphoid tissues. APRIL, along with another TNF family member, BAFF, compete for two receptors, TACI and BCMA. ARPIL has the ability to stimulate proliferation of various tumor cell lines including Jurkat T cells and MCF-7 carcinoma cells. Like BAFF, APRIL also stimulates the proliferation of B and T cells. The human APRIL gene codes for at least four alternatively spliced transcriptional variants, which give rise to different isoforms of the APRIL precursor protein. All isoforms can be cleaved by the protease, furin, to release a soluble C-terminal fragment, which comprises the TNF like receptor binding of the APRIL precursor. Recombinant murine APRIL is a soluble 21.9 kDa protein, consisting of 192 amino acid residues.

APRIL (a proliferation-inducing ligand) was identified in 1998 through database mining, and is a member of the TNF (tumor necrosis factor) family. APRIL gene is localized to human chromosome 17p13, contains six exons, and is alternatively transcribed to 1.8, 2.1, and 2.4 kb mRNA transcripts. APRIL protein is composed of a cytosolic domain of 28 amino acids, and a transmembrane region. It also contains an exoplasmic region, made up of a stalk and a TNF domain. It shares the highest similarity to BLyS (B lymphocyte stimulator) protein, ~30% sequence similarity in the TNF domain. It is synthesized as a type II transmembrane protein, and is proteolytically processed as a mature protein, which is a soluble and non-covalent trimer. Recombinant murine APRIL is a soluble 21.9 kDa protein, consisting of 192 amino acid residues.

Physical form

Lyophilized from 10 mM Sodium Acetate, pH 5.0 + 100 mM Arginine.

Reconstitution

Centrifuge the vial prior to opening. Reconstitute in water to a concentration of 0.1-1.0 mg/ml. Do not vortex. This solution can be stored at 2-8°C for up to 1 week. For extended storage, it is recommended to further dilute in a buffer containing a carrier protein (example 0.1% BSA) and store in working aliquots at -20°C to -80°C.

Sequence

MRREVSRLQR SGGPSQKQGE RPWQSLWEQS PDVLEAWKDG AKSRRRRAVL TQKHKKKHSV LHLVPVNITS KDSDVTEVMW QPVLRRGRGL EAQGDIVRVW DTGIYLLYSQ VLFHDVTFTM GQVVSREGQG RRETLFRCIR SMPSDPDRAY NSCYSAGVFH LHQGDIITVK IPRANAKLSL SPHGTFLGFV KL