Specific phosphorylation of a protein in calcium accumulating endoplasmic reticulum from rat parotid glands following stimulation by agonists involving cAMP as second messenger

FEBS Letters

Immelmann, Andreas¹  Jahn, Reinhard¹  Bode, Christa¹  Plewe, Gerd¹  Söling, Hans-Dieter¹ 

[1] Abteilung für Klinische Biochemie, Zentrum Innere Medizin der Universität Göttingen, Humboldtallee 1, D-34 Göttingen, FRG

关键词: Protein phosphorylation;    Parotid gland;    cAMP;    Endoplasmic reticulum;    Calcium;    Hepes;    N-2-hydroxyethylpiperazine-N′-ethanesulfonic acid;   

DOI  :  10.1016/0014-5793(84)80052-6

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Stimulation of secretion in exocrine cells by agonists involving cAMP as second messenger is associated with the phosphorylation of a specific membrane-associated 22.4-kDa protein (protein III) (Jahn). Here it is shown by subcellular fractionation of rat parotid gland lobules that protein III is associated with the endoplasmic reticulum. The submicrosomal fractions containing protein III, also contain the ATP-dependent microsomal calcium pump activity. Protein III in microsomal subfractions can be phosphorylated in vitro with catalytic subunit from cAMP-dependent protein kinase. Phosphorylated protein III contains exclusively P-serine. Protein III can be removed from ER-membranes with acid chloroform—methanol or Triton X-114, but not by high salt wash indicating that it is tightly associated with the membranes. Protein III is smaller than phospholamban and, in contrast to phospholamban, resistant to heating in SDS. A relationship between phosphorylation of protein III and microsomal calcium sequestration is discussed.

【 授权许可】

Unknown