Apolipoprotein-J (CLU) Rat Recombinant Protein

The protein encoded by this gene is a secreted chaperone that can under some stress conditions also be found in the cell cytosol. It has been suggested to be involved in several basic biological events such as cell death, tumor progression, and neurodegenerative disorders.[provided by RefSeq, May 2011]

CLU: Isoform 1 functions as extracellular chaperone that prevents aggregation of nonnative proteins. Prevents stress- induced aggregation of blood plasma proteins. Inhibits formation of amyloid fibrils by APP, APOC2, B2M, CALCA, CSN3, SNCA and aggregation-prone LYZ variants (in vitro). Does not require ATP. Maintains partially unfolded proteins in a state appropriate for subsequent refolding by other chaperones, such as HSPA8/HSC70. Does not refold proteins by itself. Binding to cell surface receptors triggers internalization of the chaperone-client complex and subsequent lysosomal or proteasomal degradation. Secreted isoform 1 protects cells against apoptosis and against cytolysis by complement. Intracellular isoforms interact with ubiquitin and SCF (SKP1-CUL1-F-box protein) E3 ubiquitin-protein ligase complexes and promote the ubiquitination and subsequent proteasomal degradation of target proteins. Promotes proteasomal degradation of COMMD1 and IKBKB. Modulates NF-kappa-B transcriptional activity. Nuclear isoforms promote apoptosis. Mitochondrial isoforms suppress BAX-dependent release of cytochrome c into the cytoplasm and inhibit apoptosis. Plays a role in the regulation of cell proliferation. Belongs to the clusterin family. 5 isoforms of the human protein are produced by alternative splicing.

Protein type: Secreted, signal peptide; Secreted; Mitochondrial; Apoptosis

Cellular Component: extracellular matrix; extracellular space; neuron projection; growth cone; mitochondrion; endoplasmic reticulum; perinuclear region of cytoplasm; mitochondrial membrane; cytoplasm; cytosol; nucleus

Molecular Function: protein binding; ubiquitin protein ligase binding; ATPase activity; protein N-terminus binding; misfolded protein binding

Biological Process: response to light stimulus; response to misfolded protein; positive regulation of nitric oxide biosynthetic process; protein stabilization; positive regulation of apoptosis; response to virus; cell morphogenesis; microglial cell activation; positive regulation of tumor necrosis factor production; endocrine pancreas development; negative regulation of protein homooligomerization; activation of NF-kappaB transcription factor; myelin maintenance in the central nervous system; positive regulation of proteasomal ubiquitin-dependent protein catabolic process; positive regulation of cell proliferation; protein import; response to wounding; spermatogenesis; response to oxidative stress; positive regulation of cell differentiation; chaperone-mediated protein complex assembly; neurite morphogenesis; negative regulation of apoptosis; aging