ALG-2 oscillates in subcellular localization, unitemporally with calcium oscillations

• Published in: Biochemical and biophysical research communications Vol. 353; no. 4; pp. 1063 - 1067
• Main Authors: la Cour, Jonas M., Mollerup, Jens, Berchtold, Martin Werner
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 23.02.2007
• Subjects: Adenosine Triphosphate - pharmacology; Apoptosis linked gene 2; Apoptosis Regulatory Proteins - genetics; Apoptosis Regulatory Proteins - metabolism; Ca 2+ oscillations; Ca 2+-binding proteins; Calcium - metabolism; Calcium Signaling - physiology; Calcium-Binding Proteins - genetics; Calcium-Binding Proteins - metabolism; Carrier Proteins - metabolism; Cell Line, Tumor; COPII; Cytoplasm - metabolism; Electrophoresis, Polyacrylamide Gel; Green Fluorescent Proteins - genetics; Green Fluorescent Proteins - metabolism; HeLa Cells; Histamine - pharmacology; Humans; Immunohistochemistry; Immunoprecipitation; Microscopy, Confocal; Mutation; Protein Binding; Protein Transport - drug effects; Protein Transport - physiology; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - metabolism; Time Factors; Trafficking; Transfection; Vesicular Transport Proteins; DTT; Trafficking; IgG; hEGF; EGFP; COPII; ALG-2; AIP1; MDCK; Ca 2+-binding proteins; BAPTA; PBS; Alix; COP; MALDI; IP; TBST; [Ca 2+] i; TOF; AM; EDTA; SDS–PAGE; ER; PEF; Ca 2+ oscillations; Apoptosis linked gene 2
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/j.bbrc.2006.12.143

A variety of stimuli can trigger intracellular calcium oscillations. Relatively little is known about the molecular mechanisms decoding these events. We show that ALG-2, a Ca 2+-binding protein originally isolated as a protein associated with apoptosis, is directly linked to Ca 2+ signalling. We discovered that the subcellular distribution of a tagged version of ALG-2 could be directed by physiological external stimuli (including ATP, EGF, prostaglandin, histamine), which provoke intracellular Ca 2+ oscillations. Cellular stimulation led to a redistribution of ALG-2 from the cytosol to a punctate localization in an oscillatory fashion unitemporally with Ca 2+ oscillations, whereas a Ca 2+-binding deficient mutant of ALG-2 did not redistribute. Using tagged ALG-2 as bait we identified its novel target protein Sec31A and based on the partial colocalization of endogenous ALG-2 and Sec31A we propose that ALG-2 temporarily binds to the COPII vesicles providing a link between Ca 2+ signalling and ER to Golgi trafficking.