NOVEL SECRETORY PROLINE-RICH PROTEOGLYCANS FROM RAT PAROTID - CLONING AND CHARACTERIZATION BY EXPRESSION IN ATT-20 CELLS

作者：CASTLE AM^*; CASTLE JD

来源：Journal of Biological Chemistry, 1993, 268(27): 20490-20496.

We have isolated two cDNAs that encode backbones of proline-rich proteoglycans identified previously in parotids of isoproterenol-treated rats (Blair, A. E., Castle, A. M., and Castle, J. D. (1991) Am. J. Physiol. 30, C897-C905). The sequences and domain structure of these cDNAs are characteristic of acidic proline-rich proteins, and potential glycosaminoglycan attachment sites are present within the acidic N-terminal domain. When the cDNAs were individually expressed in a mouse pituitary cell line, AtT-20, the expressed proteins were modified to sulfated proteoglycans. As in parotid acinar cells, only a fraction of the larger backbone (M(r) = 38,000) is modified by glycosaminoglycan addition; however, most of the smaller backbone (M(r) = 30,000) appears modified. Both proteoglycans expressed in AtT-20 cells contain heparan sulfate and chondroitin sulfate, whereas the proteoglycan in parotid contained chondroitin sulfate exclusively. Both proteoglycans are targeted to the regulated secretory pathway in AtT-20 cells where they are stored more efficiently than a parotid basic proline-rich protein.

• 出版日期1993-9-25