The T4 RI antiholin has an N-terminal signal anchor release domain that targets it for degradation by DegP.
Lysis inhibition (LIN) of T4-infected cells was one of the foundational experimental systems for modern molecular genetics. In LIN, secondary infection of T4-infected cells results in a dramatically protracted infection cycle in which intracellular phage and endolysin accumulation can continue for hours. At the molecular level, this is due to the inhibition of the holin, T, by the antiholin, RI. RI is only 97 residues and contains an N-terminal hydrophobic domain and a C-terminal hydrophilic domain; expression of the latter domain fused to a secretory signal sequence is sufficient to impose LIN, due to its specific interaction with the periplasmic domain of the T holin. Here we show that the N-terminal sequence comprises a signal anchor release (SAR) domain, which causes the secretion of RI in a membrane-tethered form and then its subsequent release into the periplasm, without proteolytic processing. Moreover, the SAR domain confers both functional lability and DegP-mediated proteolytic instability on the released form of RI, although LIN is not affected in a degP host. These results are discussed in terms of a model for the activation of RI in the establishment of the LIN state.
Tran
Tram Anh T
TA
Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, TX 77843-2128, USA.
Struck
Douglas K
DK
Young
Ry
R
D000595:Amino Acid Sequence; D017122:Bacteriophage T4 / Q000235:genetics / Q000502:physiology*; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D007700:Kinetics; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000378:metabolism; D033903:Periplasmic Proteins / Q000235:genetics / Q000378:metabolism*; D012697:Serine Endopeptidases / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D014764:Viral Proteins / Q000235:genetics* / Q000378:metabolism*
D006360:Heat-Shock Proteins; D010446:Peptide Fragments; D033903:Periplasmic Proteins; D014764:Viral Proteins; C061682:DegP protease; D012697:Serine Endopeptidases
J Mol Biol. 2004 Jul 16;340(4):783-95
15223320
Proc Natl Acad Sci U S A. 2006 Dec 26;103(52):19713-8
17172454
Mol Gen Genet. 1977 Jan 7;150(1):53-61
319344
J Bacteriol. 1986 Sep;167(3):1035-42
2943725
Gene. 1986;48(1):119-31
3549457
Proc Natl Acad Sci U S A. 1988 Mar;85(5):1576-80
3278319
J Bacteriol. 1989 May;171(5):2689-96
2540154
J Bacteriol. 1990 Nov;172(11):6607-10
2146254
Proc Natl Acad Sci U S A. 1990 Nov;87(21):8227-31
2146683
Biotechnology (N Y). 1994 Nov;12(11):1107-10
7765553
J Bacteriol. 1995 Jul;177(14):4121-30
7608087
J Bacteriol. 1996 Oct;178(20):5925-9
8830688
Nucleic Acids Res. 1997 Mar 15;25(6):1203-10
9092630
Annu Rev Microbiol. 2000;54:799-825
11018145
Mol Genet Genomics. 2001 Apr;265(2):345-53
11361346
Proc Natl Acad Sci U S A. 2001 Jul 31;98(16):9348-52
11459934
Mol Microbiol. 2001 Aug;41(3):575-83
11532126
Genome Res. 2002 Apr;12(4):640-7
11932248
Proc Natl Acad Sci U S A. 2004 Apr 27;101(17):6415-20
15090650
Genetics. 1998 Apr;148(4):1539-50
9560373
Cold Spring Harb Symp Quant Biol. 1961;26:25-30
13917753
Science. 2005 Jan 7;307(5706):113-7
15637279
J Bacteriol. 2005 Oct;187(19):6631-40
16166524
Proc Natl Acad Sci U S A. 2005 Dec 6;102(49):17775-9
16303867
Genetics. 1946 Nov;31(6):620-40
17247224
J Virol. 1971 Dec;8(6):887-93
4950703