scholarly journals Regulation of Insulin Secretion by SIRT4, a Mitochondrial ADP-ribosyltransferase

2007 ◽  
Vol 282 (46) ◽  
pp. 33583-33592 ◽  
Author(s):  
Nidhi Ahuja ◽  
Bjoern Schwer ◽  
Stefania Carobbio ◽  
David Waltregny ◽  
Brian J. North ◽  
...  

Sirtuins are homologues of the yeast transcriptional repressor Sir2p and are conserved from bacteria to humans. We report that human SIRT4 is localized to the mitochondria. SIRT4 is a matrix protein and becomes cleaved at amino acid 28 after import into mitochondria. Mass spectrometry analysis of proteins that coimmunoprecipitate with SIRT4 identified insulindegrading enzyme and the ADP/ATP carrier proteins, ANT2 and ANT3. SIRT4 exhibits no histone deacetylase activity but functions as an efficient ADP-ribosyltransferase on histones and bovine serum albumin. SIRT4 is expressed in islets of Langerhans and colocalizes with insulin-expressing β cells. Depletion of SIRT4 from insulin-producing INS-1E cells results in increased insulin secretion in response to glucose. These observations define a new role for mitochondrial SIRT4 in the regulation of insulin secretion.

1979 ◽  
Vol 57 (6) ◽  
pp. 737-748 ◽  
Author(s):  
Theo Hofmann ◽  
Michiko Kawakami ◽  
Anthony J. W. Hitchman ◽  
Joan E. Harrison ◽  
Keith J. Dorrington

The complete amino acid sequence of the calcium-binding protein (CaBP) from pig intestinal mucosa has been determined: Ac-Ser-Ala-Gln-Lys-Ser-Pro-Ala-Glu-Leu-Lys-Ser-Ile-Phe-Glu-Lys-Tyr-Ala-Ala-Lys-Glu-Gly-Asp-Pro-Asn-Gln-Leu-Ser-Lys-Glu-Glu-Leu-Lys-Gln-Leu-Ile-Gln-Ala-Glu-Phe-Pro-Ser-Leu-Leu-Lys-Gly-Pro-Arg-Thr-Leu-Asp-Asp-Leu-Phe-Gln-Glu-Leu-Asp-Lys-Asn-Gly-Asn-Gly-Glu-Val-Ser-Phe-Glu-Glu-Phe-Gln-Val-Leu-Val-Lys-Lys-Ile-Ser-Gln-OH. The N-terminal octapeptide sequence was determined by mass spectrometry analysis by Morris and Dell. The first 45 residues of bovine CaBP differ only in six positions from the corresponding sequence of the porcine protein, except that the sequence starts in position two of the porcine sequence. The mammalian intestinal CaBP's belong to the troponin-C superfamily on the basis of an analysis by Barker and Dayhoff.


Toxicon ◽  
2008 ◽  
Vol 51 (8) ◽  
pp. 1499-1508 ◽  
Author(s):  
Elisabeth F. Schwartz ◽  
Thalita S. Camargos ◽  
Fernando Z. Zamudio ◽  
Luciano P. Silva ◽  
Carlos Bloch ◽  
...  

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Humaira Saleh Syed ◽  
Rishimol R ◽  
Arun Kumar J ◽  
M Masilamani Selvam ◽  
Rajesh R P

Conus loroisii is a marine vermivorous snail found profusely in the southern seas of India. They harbor several toxic peptide components commonly called as ‘conotoxins’. In this study, we have identified and sequenced five conotoxins using proteome based tandem mass spectrometry analysis through Data analysis 4.1 software. Among them, we found Lo959 as contryphan which is previously described. All other conotoxins Lo1702, Lo1410, Lo1385 and Lo1686 belong to M-Superfamily conotoxins and novel to C. loroisii. Lo1410 is completely novel to conotoxin research with 3 disulfides and the amino acid sequence is derived as CCSTNCAVCIPCCP. All the identified M-Superfamily conotoxins are sub categorised to mini M2 superfamily conotoxins. Lo1702 and Lo1686 possess C- terminal amidation which is the key feature in conotoxins.  Moreover, we have screened the natural venom for the occurrence of toxicity in the zebrafish model and brine shrimp. 


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