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Effects of serum on calcium mobilization in the submandibular cell line A253
Author(s) -
Sun Xiuhua,
Mörk AnnChristin,
Helmke R.J.,
Martinez J. Ricardo,
Zhang Guo H.
Publication year - 1999
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/(sici)1097-4644(19990615)73:4<458::aid-jcb4>3.0.co;2-0
Subject(s) - bovine serum albumin , fetal bovine serum , thapsigargin , chemistry , cytosol , calcium , intracellular , tyrosine kinase , medicine , endocrinology , cell , biology , signal transduction , biochemistry , enzyme
The effects of serum on inositol 1,4,5‐trisphosphate (IP 3 ) formation and Ca 2+ mobilization in the human submandibular cell line A253 were studied. Exposure of A253 cells to fetal bovine serum (FBS) elicited a 3.3‐fold increase in IP 3 formation and a concentration‐dependent transient increase in cytosolic free Ca 2+ concentration ([Ca 2+ ] i ), which was similar in Ca 2+ ‐containing and Ca 2+ ‐free media. Newborn bovine serum (NBS), but not bovine serum albumin (BSA), induced a similar response. The Ca 2+ release triggered by FBS was significantly (88%) reduced by the phospholipase C inhibitor U73122, indicating that Ca 2+ release induced by FBS is through the PLC pathway. Pretreatment with the tyrosine kinase inhibitor genistein abolished the FBS‐ and NBS‐induced Ca 2+ release, suggesting that tyrosine kinase plays an important role in mediating the Ca 2+ release. Pre‐exposure to ATP or thapsigargin (TG) significantly reduced the FBS‐induced [Ca 2+ ] i increase, indicating that Ca 2+ release caused by FBS is from the TG‐ or ATP‐sensitive Ca 2+ store. While FBS exposure elicited a large Ca 2+ release, it reduced Ca 2+ influx. Furthermore, FBS significantly inhibited the Ca 2+ influx activated by the depletion of intracellular stores by ATP or TG. These results suggest that (1) serum elicits Ca 2+ release from ATP‐ and TG‐sensitive stores, which is mediated by IP 3 ; (2) the serum‐induced Ca 2+ release may be modulated by a tyrosine kinase‐associated process; and (3) serum strongly inhibits Ca 2+ influxes including the store depletion‐activated Ca 2+ influx. J. Cell. Biochem. 73:458–468, 1999. © 1999 Wiley‐Liss, Inc.