Manual transfer of experimentally-verified manual GO annotation data to orthologs by curator judgment of sequence similarity
Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location vocabulary mapping, accompanied by conservative changes to GO terms applied by UniProt
Widespread control of calcium signaling by a family of SERCA-inhibiting micropeptides.
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Endoregulin was identified in a mouse-genome screen for the SERCA-binding motif; the mouse peptide localises to the ER, binds SERCA2b competitively with PLN, and lowers the apparent Ca2+ affinity of SERCA3a.
"we used a bioinformatics approach to screen the mouse genome for potential open reading frames containing the SERCA binding motif of MLN, PLN, and SLN"
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ELN is expressed mainly in non-muscle epithelia, overlapping SERCA3.
"ELN expression showed a large degree of overlap with that of SERCA3 in the epithelial cells of the trachea and bronchus, lung, intestine, pancreas, and liver"
Nothing Regular about the Regulins: Distinct Functional Properties of SERCA Transmembrane Peptide Regulatory Subunits.
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Recombinant human ELN co-reconstituted with purified SERCA1a lowers the pump's Vmax without changing KCa.
"whereas ELN selectively alters the turnover rate (Vmax) of SERCA (Figure 7C)"
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The reconstitution used SERCA1a rather than ELN's presumed physiological partner SERCA3a.
"It should be noted that our reconstitution system used SERCA1a, while the primary targets of ALN and ELN are SERCA2b and SERCA3a, respectively."
Newly Discovered Micropeptide Regulators of SERCA Form Oligomers but Bind to the Pump as Monomers.
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ELN, like the other regulins, forms homo-oligomers but binds SERCA as a monomer.
"Micropeptides formed avid homo-oligomers with high-order stoichiometry (n > 2 protomers per homo-oligomer), but it was the monomeric form of all micropeptides that interacted with SERCA."
Micropeptide hetero-oligomerization adds complexity to the calcium pump regulatory network.
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Human ELN forms hetero-oligomers with PLN, SLN, ALN and DWORF with affinities comparable to homo-oligomerisation.
"human sequences of all micropeptides (PLB, SLN, DWORF, ALN, and ELN) were labeled using either mCerulean or YFP"
Rapid quantification of intracellular calcium stores reveals effects of membrane micropeptides on SERCA function.
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ELN expression lowers ER Ca2+ content in live cells, less potently than PLN.
"Sarcolipin (SLN), endoregulin (ELN), and another-regulin (ALN) also decreased ER Ca2+ content, though less potently than PLB."