Selenoprotein K Increases Efficiency of DHHC6 Catalyzed Protein Palmitoylation by Stabilizing the Acyl-DHHC6 Intermediate
Selenoprotein K (SELENOK) is a selenocysteine (Sec)-containing protein localized in the endoplasmic reticulum (ER) membrane where it interacts with the DHHC6 (where single letter symbols represent Asp-His-His-Cys amino acids) enzyme to promote protein acyl transferase (PAT) reactions. PAT reactions...
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| Format: | Article |
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MDPI AG
2017-12-01
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| Series: | Antioxidants |
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| Online Access: | https://www.mdpi.com/2076-3921/7/1/4 |
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| author | Gregory J. Fredericks FuKun W. Hoffmann Robert J. Hondal Sharon Rozovsky Johann Urschitz Peter R. Hoffmann |
| author_facet | Gregory J. Fredericks FuKun W. Hoffmann Robert J. Hondal Sharon Rozovsky Johann Urschitz Peter R. Hoffmann |
| author_sort | Gregory J. Fredericks |
| collection | DOAJ |
| description | Selenoprotein K (SELENOK) is a selenocysteine (Sec)-containing protein localized in the endoplasmic reticulum (ER) membrane where it interacts with the DHHC6 (where single letter symbols represent Asp-His-His-Cys amino acids) enzyme to promote protein acyl transferase (PAT) reactions. PAT reactions involve the DHHC enzymatic capture of palmitate via a thioester bond to cysteine (Cys) residues that form an unstable palmitoyl-DHHC intermediate, followed by transfer of palmitate to Cys residues of target proteins. How SELENOK facilitates this reaction has not been determined. Splenocyte microsomal preparations from wild-type mice versus SELENOK knockout mice were used to establish PAT assays and showed decreased PAT activity (~50%) under conditions of SELENOK deficiency. Using recombinant, soluble versions of DHHC6 along with SELENOK containing Sec92, Cys92, or alanine (Ala92), we evaluated the stability of the acyl-DHHC6 intermediate and its capacity to transfer the palmitate residue to Cys residues on target peptides. Versions of SELENOK containing either Ala or Cys residues in place of Sec were equivalently less effective than Sec at stabilizing the acyl-DHHC6 intermediate or promoting PAT activity. These data suggest that Sec92 in SELENOK serves to stabilize the palmitoyl-DHHC6 intermediate by reducing hydrolyzation of the thioester bond until transfer of the palmitoyl group to the Cys residue on the target protein can occur. |
| first_indexed | 2024-03-12T08:18:05Z |
| format | Article |
| id | doaj.art-b13ec90a8b6843b28e46bbdf45a5661c |
| institution | Directory Open Access Journal |
| issn | 2076-3921 |
| language | English |
| last_indexed | 2024-03-12T08:18:05Z |
| publishDate | 2017-12-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Antioxidants |
| spelling | doaj.art-b13ec90a8b6843b28e46bbdf45a5661c2023-09-02T18:43:44ZengMDPI AGAntioxidants2076-39212017-12-0171410.3390/antiox7010004antiox7010004Selenoprotein K Increases Efficiency of DHHC6 Catalyzed Protein Palmitoylation by Stabilizing the Acyl-DHHC6 IntermediateGregory J. Fredericks0FuKun W. Hoffmann1Robert J. Hondal2Sharon Rozovsky3Johann Urschitz4Peter R. Hoffmann5Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, 651 Ilalo Street, Honolulu, HI 96813, USADepartment of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, 651 Ilalo Street, Honolulu, HI 96813, USADepartment of Biochemistry, University of Vermont, 89 Beaumont Ave, Given Building Room B413, Burlington, VT 05405, USADepartment of Chemistry and Biochemistry, University of Delaware, 136 Brown Laboratory, Newark, DE 19716, USADepartment of Anatomy, Biochemistry and Physiology, John A. Burns School of Medicine, University of Hawaii, 651 Ilalo Street, Honolulu, HI 96813, USADepartment of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, 651 Ilalo Street, Honolulu, HI 96813, USASelenoprotein K (SELENOK) is a selenocysteine (Sec)-containing protein localized in the endoplasmic reticulum (ER) membrane where it interacts with the DHHC6 (where single letter symbols represent Asp-His-His-Cys amino acids) enzyme to promote protein acyl transferase (PAT) reactions. PAT reactions involve the DHHC enzymatic capture of palmitate via a thioester bond to cysteine (Cys) residues that form an unstable palmitoyl-DHHC intermediate, followed by transfer of palmitate to Cys residues of target proteins. How SELENOK facilitates this reaction has not been determined. Splenocyte microsomal preparations from wild-type mice versus SELENOK knockout mice were used to establish PAT assays and showed decreased PAT activity (~50%) under conditions of SELENOK deficiency. Using recombinant, soluble versions of DHHC6 along with SELENOK containing Sec92, Cys92, or alanine (Ala92), we evaluated the stability of the acyl-DHHC6 intermediate and its capacity to transfer the palmitate residue to Cys residues on target peptides. Versions of SELENOK containing either Ala or Cys residues in place of Sec were equivalently less effective than Sec at stabilizing the acyl-DHHC6 intermediate or promoting PAT activity. These data suggest that Sec92 in SELENOK serves to stabilize the palmitoyl-DHHC6 intermediate by reducing hydrolyzation of the thioester bond until transfer of the palmitoyl group to the Cys residue on the target protein can occur.https://www.mdpi.com/2076-3921/7/1/4palmitic acidpalmitoyl-CoApalmitoylationinositol 1,4,5-triphosphate receptorANK repeat and PH domain-containing protein 2 (ASAP2)cluster of differentiation (CD36)seleniumthioester |
| spellingShingle | Gregory J. Fredericks FuKun W. Hoffmann Robert J. Hondal Sharon Rozovsky Johann Urschitz Peter R. Hoffmann Selenoprotein K Increases Efficiency of DHHC6 Catalyzed Protein Palmitoylation by Stabilizing the Acyl-DHHC6 Intermediate Antioxidants palmitic acid palmitoyl-CoA palmitoylation inositol 1,4,5-triphosphate receptor ANK repeat and PH domain-containing protein 2 (ASAP2) cluster of differentiation (CD36) selenium thioester |
| title | Selenoprotein K Increases Efficiency of DHHC6 Catalyzed Protein Palmitoylation by Stabilizing the Acyl-DHHC6 Intermediate |
| title_full | Selenoprotein K Increases Efficiency of DHHC6 Catalyzed Protein Palmitoylation by Stabilizing the Acyl-DHHC6 Intermediate |
| title_fullStr | Selenoprotein K Increases Efficiency of DHHC6 Catalyzed Protein Palmitoylation by Stabilizing the Acyl-DHHC6 Intermediate |
| title_full_unstemmed | Selenoprotein K Increases Efficiency of DHHC6 Catalyzed Protein Palmitoylation by Stabilizing the Acyl-DHHC6 Intermediate |
| title_short | Selenoprotein K Increases Efficiency of DHHC6 Catalyzed Protein Palmitoylation by Stabilizing the Acyl-DHHC6 Intermediate |
| title_sort | selenoprotein k increases efficiency of dhhc6 catalyzed protein palmitoylation by stabilizing the acyl dhhc6 intermediate |
| topic | palmitic acid palmitoyl-CoA palmitoylation inositol 1,4,5-triphosphate receptor ANK repeat and PH domain-containing protein 2 (ASAP2) cluster of differentiation (CD36) selenium thioester |
| url | https://www.mdpi.com/2076-3921/7/1/4 |
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