HIV-1反式激活因子（Tat）蛋白的弗林蛋白酶切割

Furin cleavage of the HIV-1 Tat protein.

作者信息

Tikhonov Ilia, Ruckwardt Tracy J, Berg Shannon, Hatfield Glen S, David Pauza C

机构信息

Institute of Human Virology, University of Maryland Biotechnology Institute, 725 W. Lombard St. Rm. N533, Baltimore, MD 21201, USA.

出版信息

FEBS Lett. 2004 May 7;565(1-3):89-92. doi: 10.1016/j.febslet.2004.03.079.

DOI:10.1016/j.febslet.2004.03.079

PMID:15135058

Abstract

Extracellular human immunodeficiency virus-1 (HIV-1) Tat protein and Tat-derived peptides are biologically active but mechanisms of Tat processing are not known. Within the highly conserved basic region of HIV-1 Tat protein (amino acids, a.a. 48-56), we identified two putative furin cleavage sites and showed that Tat protein was cleaved in vitro at the second site, RQRR\ (a.a. 53-56). This in vitro cleavage was blocked by a monoclonal antibody that binds near the cleavage site or by the furin inhibitor alpha-1 PDX. Monocytoid cells rich in furin also degraded Tat and this process was slowed by the furin inhibitor or the specific monoclonal antibody. Furin processing did not affect the rates for Tat uptake and nuclear accumulation in HeLa or Jurkat cells, but the transactivation activity was greatly reduced. Furin processing is a likely mechanism for inactivating extracellular HIV-1 Tat protein.

摘要

细胞外人类免疫缺陷病毒1型（HIV-1）反式激活因子（Tat）蛋白和Tat衍生肽具有生物活性，但Tat的加工机制尚不清楚。在HIV-1 Tat蛋白的高度保守碱性区域（氨基酸48-56位）内，我们鉴定出两个假定的弗林蛋白酶切割位点，并表明Tat蛋白在体外第二个位点RQRR（氨基酸53-56位）处被切割。这种体外切割被结合在切割位点附近的单克隆抗体或弗林蛋白酶抑制剂α-1 PDX所阻断。富含弗林蛋白酶的单核细胞样细胞也会降解Tat，并且这个过程会被弗林蛋白酶抑制剂或特异性单克隆抗体所减缓。弗林蛋白酶加工不影响Tat在HeLa或Jurkat细胞中的摄取和核积累速率，但反式激活活性大大降低。弗林蛋白酶加工可能是使细胞外HIV-1 Tat蛋白失活的一种机制。