Caspase‐mediated proteolysis during apoptosis: insights from apoptotic neutrophils

FEBS Letters

Rosen, Antony³  Casciola-Rosen, Livia¹  Thelen, Marcus⁴  Thornberry, Nancy A²  Sanghavi, Darshak M³ 

[1] Department of Dermatology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA;Department of Enzymology, Merck Research Laboratories, Rahway, NJ 07065, USA;Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA;Theodor Kocher Institut, Berne, Switzerland

关键词: Caspase;    Proteolysis;    Apoptosis;   

DOI  :  10.1016/S0014-5793(98)00004-0

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Apoptosis is initiated by activation of caspases (interleukin 1β-converting enzyme homologues), which cause coordinated cleavage of several death substrates that function in structural or homeostatic pathways. The relationship between substrate cleavage and apoptosis is not yet known, nor is it clear whether cleavage of specific substrates is a critical requirement for apoptosis. The human neutrophil provides novel insights into the roles of proteolysis of specific substrates during apoptosis, since only a subset of caspase substrates are present in mature neutrophils. Of the death substrates we screened, PARP, the nuclear mitotic apparatus protein (NuMA), the 70 kDa subunit of the U1 small ribonucleoprotein (U1-70kDa) and the catalytic subunit of DNA-dependent protein kinase (DNA-PK_cs) were not detected in non-apoptotic neutrophils; in contrast, lamin B and fodrin were present in amounts similar to those found in other cells. Caspase-3 activity was absent in freshly isolated neutrophils, but was detected when neutrophils were aged in vitro, coincident with the onset of morphologic and biochemical apoptosis. The absence of PARP, NuMA, U1-70kDa and DNA-PK_cs in non-apoptotic neutrophils suggests that these are not critical anti-apoptotic proteins, and that their fragments are not required components of the neutrophil apoptotic pathway. These studies highlight the conserved role of caspase activation in the apoptotic mechanism, and focus attention on several conserved structural substrates as potential transducers of the proteolytic signal in apoptosis.

【 授权许可】

Unknown