| 1997 |
Calumenin is a Ca2+-binding protein with six EF-hand motifs retained in the endoplasmic reticulum; the C-terminal tetrapeptide HDEF is responsible for ER retention, with the Phe residue being a novel component of the ER retention signal. |
Retention assay, immunostaining with confocal laser microscope, deglycosylation assay, Ca2+-binding assay with purified protein |
The Journal of biological chemistry |
High |
9218460
|
| 1998 |
Recombinant human calumenin binds Ca2+ through all 7 EF-hand domains with low affinity (Kd ~1/1.6×10³ M⁻¹ per site), consistent with a role in Ca2+-dependent ER processes. |
Microdialysis Ca2+-binding experiments with recombinant human calumenin expressed in E. coli |
Biochimica et biophysica acta |
High |
9675259
|
| 1999 |
Human calumenin localizes to both the ER and Golgi complex in multiple human cell lines, and a glycosylated, endoglycosidase H-resistant form is secreted into the culture medium, indicating transit through the Golgi and extracellular release. |
Immunofluorescence, immunoelectron microscopy, endoglycosidase H treatment, Western blot of conditioned medium |
Experimental cell research |
High |
10222138
|
| 2000 |
Calumenin binds serum amyloid P component (SAP) in a Ca2+-dependent manner; this interaction was identified by affinity chromatography and verified by surface plasmon resonance. |
Affinity chromatography with immobilized recombinant calumenin, amino acid sequencing of eluate, surface plasmon resonance |
FEBS letters |
Medium |
10631319
|
| 2006 |
Calumenin-2 interacts with ryanodine receptor 1 (RyR1) in rabbit skeletal sarcoplasmic reticulum in a Ca2+-dependent manner; the second EF-hand domain of calumenin is essential for this interaction. Overexpression of calumenin-2 in C2C12 myotubes increases caffeine-induced Ca2+ release but decreases depolarization-induced Ca2+ release. |
GST pull-down, co-immunoprecipitation, EF-hand deletion constructs, adenovirus-mediated overexpression, Ca2+ imaging |
Biochemical and biophysical research communications |
High |
16527250
|
| 2008 |
Calumenin overexpression in neonatal rat cardiomyocytes prolongs time to 50% Ca2+ baseline (T50) by inhibiting SERCA2-mediated Ca2+ uptake into the SR; co-immunoprecipitation demonstrates a direct interaction between calumenin and SERCA2. |
Adenovirus-mediated overexpression, Ca2+ transient measurement, oxalate-supported Ca2+ uptake assay, co-immunoprecipitation |
Molecules and cells |
High |
18562801
|
| 2009 |
Calumenin (calu-1) in C. elegans is required for fertility, locomotion, body size, defecation, and pharyngeal pumping; genetic analysis suggests calu-1 regulates pharyngeal pumping together with the IP3 receptor (itr-1). |
Mutant analysis, genetic epistasis (calu-1 and itr-1 double mutant analysis), behavioral assays |
FEBS letters |
Medium |
19695248
|
| 2009 |
Calumenin interacts with SERCA2 in mouse cardiac SR; the binding is favored in the E1 state of SERCA2 (reduced by thapsigargin, vanadate, or ATP). GST pull-down with deletion fragments maps the interaction to residues 132–222 of calumenin and residues 853–892 (L4 luminal domain) of SERCA2. Calumenin knockdown (80%) in HL-1 cells enhances Ca2+ transient amplitude and increases Ca2+ sensitivity of SERCA2. |
GST pull-down with deletion fragments, co-immunoprecipitation, immunocytochemistry, siRNA knockdown, oxalate-supported Ca2+ uptake assay, state-specific SERCA2 inhibitors |
The Journal of biological chemistry |
High |
19740751
|
| 2012 |
Calumenin-1/2 secretion requires microtubule integrity and is mediated by motor proteins Kif5b and cytoplasmic dynein; the export signal maps to amino acids 20–46, and asparagine at position 131 is required for protein stabilization. |
Time-lapse live-cell imaging of calu-1/2-EGFP, microtubule disruption, dominant-negative motor protein expression, deletion mapping |
PloS one |
Medium |
22514732
|
| 2012 |
Calumenin is identified as a binding partner of G551D-CFTR by co-immunoprecipitation and mass spectrometry, and is more abundant in the G551D-CFTR complex than in the wild-type CFTR complex; the interaction was confirmed by surface plasmon resonance. |
Co-immunoprecipitation, 2D-gel electrophoresis, mass spectrometry, surface plasmon resonance, immunofluorescence |
PloS one |
Medium |
22768251
|
| 2013 |
Calumenin overexpression in neonatal rat ventricular cardiomyocytes reduces ER stress markers (GRP78, p-PERK, p-eIF2α) and ER-initiated apoptosis markers (CHOP, p-JNK) during tunicamycin-induced ER stress, and reduces apoptosis as measured by TUNEL assay. |
Recombinant adenovirus-mediated overexpression (7.5-fold), Western blot for ER stress markers, TUNEL assay |
Biochemical and biophysical research communications |
Medium |
24012670
|
| 2013 |
Calumenin isoform Calu-15 promotes filopodia formation and cell migration by: (1) shuttling between nucleus and cytoplasm via interaction with importin α, Ran GTPase, and CRM1; (2) requiring CK2-dependent phosphorylation of Thr-73 for nuclear import; and (3) binding the GDF-15 promoter in the nucleus to increase GDF-15 transcription. |
Alternative splicing cloning, co-immunoprecipitation (importin α, Ran, CRM1), CK2 inhibition, Thr-73 point mutation, chromatin immunoprecipitation, promoter-reporter assay, filopodia imaging |
Cell death & disease |
Medium |
24136234
|
| 2014 |
Extracellular calumenin binds and stabilizes fibulin-1, protecting it from MMP-13-mediated proteolysis; this suppresses ERK1/2 signaling and inhibits cell migration. The minimal functional domain maps to residues 74–138 and 214–280. Calumenin/fibulin-1 also interact with fibronectin and signal through syndecan-4 and α5β1-integrin to suppress pERK1/2. |
Co-immunoprecipitation, siRNA knockdown, in vitro MMP-13 cleavage protection assay, ERK1/2 phosphorylation Western blot, migration assay, domain deletion mapping |
Oncogene |
High |
24632605
|
| 2014 |
Calumenin reduces F508del-CFTR aggregation in vitro, similar to an intrinsically disordered protein (IDP), and shows altered trafficking in bronchial cells expressing F508del-CFTR, indicating a direct role in mutant CFTR folding/processing. |
Aggregation assay (recombinant calumenin + F508del-CFTR), fluorescence microscopy-based trafficking analysis, biophysical characterization |
PloS one |
Medium |
25120007
|
| 2015 |
CALU polymorphism rs1043550 (A29809G) reduces calumenin mRNA stability by ~30% as shown by a luciferase reporter assay in vascular cells; reduced calumenin availability correlates with impaired gamma-carboxylation of matrix-Gla-protein and altered vascular calcification. |
Luciferase reporter system (mRNA stability assay), immunohistochemistry, clinical genotyping, extracellular matrix mineralization assay in hVSMC |
Journal of molecular and cellular cardiology |
Medium |
25823396
|
| 2015 |
Calumenin and reticulocalbin interact with fibulin-1C, C1 esterase inhibitor, and GRP75 (Grp75); calumenin binds fibulin-1C with Kd ~50–60 nM and C1 esterase inhibitor with Kd ~150 nM; the calumenin–C1 esterase inhibitor interaction is Ca2+-dependent (detectable at 3.5 mM, absent at 0.1 mM Ca2+). |
Affinity purification, co-immunoprecipitation, mass spectrometry, surface plasmon resonance |
PloS one |
Medium |
26161649
|
| 2016 |
Calumenin undergoes Ca2+-induced folding: in low Ca2+, the protein is largely disordered; upon Ca2+ addition it adopts a compact, predominantly alpha-helical trilobal structure. This conformational switch is reversible. |
Circular dichroism spectroscopy, small-angle X-ray scattering (SAXS), analytical size-exclusion chromatography, surface plasmon resonance |
PloS one |
High |
26991433
|
| 2017 |
Calumenin modulates SERCA pump activity and is a key regulator of ER Ca2+ homeostasis in bronchial epithelial cells expressing both wild-type and F508del-CFTR; reducing calumenin expression partially restores F508del-CFTR activity. |
siRNA knockdown, ER Ca2+ measurement, SERCA activity assay, CFTR functional assay |
Cell calcium |
Medium |
28189267
|
| 2026 |
Calumenin acts as a chaperone for vimentin proteostasis in lung fibroblasts: it collaborates with the TRiC chaperonin complex to facilitate proper vimentin folding, and recruits the CCT2 subunit to degrade misfolded vimentin aggregates. Fibroblast-specific knockout of calumenin promotes vimentin aggregate accumulation and profibrotic factor (migracytosis) secretion, exacerbating fibroblast senescence and lung aging. External profibrotic stimuli trigger calcium transients that induce calumenin degradation. |
CRISPR-based genetic screen, fibroblast-specific knockout mouse, co-immunoprecipitation (TRiC/CCT2), live-cell imaging, Ca2+ imaging, Western blot, electron microscopy |
Proceedings of the National Academy of Sciences of the United States of America |
High |
41557802
|