PubMed Journals: EMBO J

  Source:		PMID: 9351817

    		EMBO J. 1997 Nov 3;16(21):6346-54.
			The large subunit of replication factor
			C is a substrate for caspase-3 in vitro
			and is cleaved by a caspase-3-like protease
			during Fas-mediated apoptosis.

			Rhéaume E(1), Cohen LY, Uhlmann F, Lazure
			C, Alam A, Hurwitz J, Sékaly RP, Denis F.

			Author Information
			(1) Laboratoire d'Immunologie, Institut
			de recherches cliniques de Montréal, Québec,

			Caspase-3 is an ICE-like protease activated
			during apoptosis induced by different stimuli.
			Poly(ADP-ribose) polymerase (PARP), the
			first characterized substrate of caspase-3,
			shares a region of homology with the large
			subunit of Replication Factor C (RF-C),
			a five-subunit complex that is part of the
			processive eukaryotic DNA polymerase holoenzymes.
			Caspase-3 cleaves PARP at a DEVD-G motif
			present in the 140 kDa subunit of RF-C (RFC140)
			and evolutionarily conserved. We show that
			cleavage of RFC140 during Fas-mediated apoptosis
			in Jurkat cells and lymphocytes results
			in generation of multiple fragments. Cleavage
			is inhibited by the caspase-3-like protease
			inhibitor Ac-DEVD-CHO but not the caspase-1/ICE-type
			protease inhibitor Ac-YVAD-CHO. In addition,
			recombinant caspase-3 cleaves RFC140 in
			vitro at least at three different sites
			in the C-terminal half of the protein. Using
			amino-terminal microsequencing of radioactive
			fragments, we identified three sites: DEVD723G,
			DLVD922S and IETD1117A. We did not detect
			cleavage of small subunits of RF-C of 36,
			37, 38 and 40 kDa by recombinant caspase-3
			or by apoptotic Jurkat cell lysates. Cleavage
			of RFC140 during apoptosis inactivates its
			function in DNA replication and generates
			truncated forms that further inhibit DNA
			replication. These results identify RFC140
			as a critical target for caspase-3-like
			proteases and suggest that caspases could
			mediate cell cycle arrest.

			DOI: 10.1093/emboj/16.21.6346 PMCID: PMC1170241
			PMID: 9351817 [Indexed for MEDLINE]

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