Characterization of cysteine string protein in rat parotid acinar cells.
Cysteine string proteins (CSPs) are secretory vesicle chaperone proteins that contain: (i) a heavily palmitoylated cysteine string (comprised of 14 cysteine residues, responsible for the localization of CSP to secretory vesicle membranes), (ii) an N-terminal J-domain (DnaJ domain of Hsc70, 70kDa heat-shock cognate protein family of co-chaperones), and (iii) a linker domain (important in mediating CSP effects on secretion). In this study, we investigated the localization of CSP1 in rat parotid acinar cells and evaluated the role of CSP1 in parotid secretion. RT-PCR and western blotting revealed that CSP1 was expressed and associated with Hsc70 in rat parotid acinar cells. Further, CSP1 associated with syntaxin 4, but not with syntaxin 3, on the apical plasma membrane. Introduction of anti-CSP1 antibody into SLO-permeabilized acinar cells enhanced isoproterenol (IPR)-induced amylase release. Introduction of GST-CSP11-112, containing both the J-domain and the adjacent linker region, enhanced IPR-induced amylase release, whereas neither GST-CSP11-82, containing the J-domain only, nor GST-CSP183-112, containing the linker region only, did produce detectable enhancement. These results indicated that both the J-domain and the linker domain of CSP1 are necessary to function an important role in acinar cell exocytosis.
Department of Biochemistry, The Nippon Dental University, Life Dentistry at Niigata, 1-8 Hamaura-cho, Chuo-ku, Niigata 951-8580, Japan. Electronic address: hshimo@ngt.ndu.ac.jp.
Hiromi
H
Shimomura
Akane
A
Imai
Tomoko
T
Nashida
D061354:Acinar Cells / Q000166:cytology*; D000681:Amylases / Q000378:metabolism; D000818:Animals; D005089:Exocytosis; D005982:Glutathione Transferase / Q000378:metabolism; D050883:HSC70 Heat-Shock Proteins; D050956:HSP40 Heat-Shock Proteins / Q000737:chemistry*; D007545:Isoproterenol / Q000494:pharmacology; D008565:Membrane Proteins / Q000737:chemistry*; D019308:Palmitic Acid / Q000737:chemistry; D010306:Parotid Gland / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D050765:Qa-SNARE Proteins / Q000378:metabolism; D051381:Rats; D022142:Secretory Vesicles / Q000378:metabolism; D013347:Subcellular Fractions / Q000378:metabolism
D050883:HSC70 Heat-Shock Proteins; D050956:HSP40 Heat-Shock Proteins; D008565:Membrane Proteins; D050765:Qa-SNARE Proteins; C088460:cysteine string protein; D019308:Palmitic Acid; D005982:Glutathione Transferase; D000681:Amylases; D007545:Isoproterenol
Acinar cells; Amylase; Cysteine string protein; Parotid; Secretion