Human IL-1 beta processing and secretion in recombinant baculovirus-infected Sf9 cells is blocked by the cowpox virus serpin crmA.

Published

Journal Article

Biologically active, mature IL-1 beta (mIL-1 beta) is released from activated monocytes after proteolytic processing from an inactive precursor (pIL-1 beta). IL-1 beta converting enzyme (ICE), the first member of a newly discovered family of cysteine proteinases, is required for this processing event. The cleaved cytokine is released from monocytes by an unknown mechanism which does not employ a standard hydrophobic signal sequence. As in mammalian fibroblasts, insect Sf9 cells do not normally process or secrete human IL-1 beta. The expression of active ICE enables Sf9 cells to process 31-kDa pIL-1 beta correctly at Asp27 and Asp116, and to export 17.5-kDa mIL-1 beta. The recombinant heterodimeric human enzyme purified from Sf9 cells possesses a sp. act. of 2.9 +/- 0.5 x 10(6) U/mg and is indistinguishable from native ICE with regard to its subunit composition and catalytic properties. In this system, co-expression of the cowpox virus crmA gene, an extremely potent serpin inhibitor of ICE (Ki < 7 pM), inhibits ICE activation completely and blocks pIL-1 beta processing and mIL-1 beta secretion by approximately 95%. The results indicate that ICE, in addition to its processing function, facilitates the transport of IL-1 beta across the plasma membrane.

Full Text

Duke Authors

Cited Authors

  • Howard, AD; Palyha, OC; Griffin, PR; Peterson, EP; Lenny, AB; Ding, GJ; Pickup, DJ; Thornberry, NA; Schmidt, JA; Tocci, MJ

Published Date

  • March 1995

Published In

Volume / Issue

  • 154 / 5

Start / End Page

  • 2321 - 2332

PubMed ID

  • 7868902

Pubmed Central ID

  • 7868902

Electronic International Standard Serial Number (EISSN)

  • 1550-6606

International Standard Serial Number (ISSN)

  • 0022-1767

Language

  • eng