TABLE 2:
C. trachomatis non-Inc proteins secreted into the host cell cytoplasm, inclusion membrane, or inclusion lumena.
| Protein (annotation/name) | Secretion pathway; host cell protein targets; localization in infected host cells; and proposed function(s) and/or activity | References | ||
|---|---|---|---|---|
| Strain D/UW3 | Strain L2/434 | General | ||
| CT042 | CTL0298 | GlgX | Secretion: T3S; targets: N/A; localization: inclusion lumen and membrane; function: glycogen hydrolase. | [289] |
| CT049 | CTL0305 | Pls1 | Secretion: unknown but T3S-independent; targets: unknown; localization: inclusion lumen; function: unknown. | [293] |
| CT050 | CTL0306 | Pls2 | Secretion: unknown but T3S-independent; targets: unknown; localization: inclusion lumen; function: unknown. | [293] |
| CT089 | CTL0344 | CopN | Secretion: T3S; targets: unknown; localization: inclusion membrane; function: regulation of the T3S system. | [23, 50] |
| CT105 | CTL0360 | CteG | Secretion: T3S; targets: unknown; localization: Golgi and host cell plasma membrane; function: modulation of eukaryotic vesicular trafficking. | [227, 228] |
| CT142 | CTL0397 | - | Secretion: T3S; targets: unknown; localization: inclusion lumen; function: unknown. | [227, 294] |
| CT143 | CTL0398 | - | Secretion: T3S; targets: unknown; localization: inclusion lumen; function: possible involvement in inflammatory processes. | [227, 292, 294–296] |
| CT144 | CTL0399 | - | Secretion: T3S; targets: unknown; localization: inclusion lumen; function: unknown. | [227, 294, 295] |
| CT156 | Absent | Lda1 | Secretion: unknown; targets: unknown; localization: around the inclusion, overlapping with LD-like structures; function: targeting LDs. | [54, 219] |
| CT163 | CTL0419 | Lda2 | Secretion: unknown; targets: unknown; localization: around the inclusion, overlapping with LD-like structures, and within LD biochemical fractions; function: targeting LDs. | [54, 219] |
| CT311 | CTL0563 | - | Secretion: Sec-dependent/T2S; targets: unknown; localization: inclusion lumen, cytosol and nucleus; function: unknown. | [32, 279] |
| CT456 | CTL0716 | TarP | Secretion: T3S; targets: actin, ABI1, VAV2, PI3K p85 subunit, SHC1; localization: cytosol, near the nascent inclusion, and membrane fractions of infected cells; function: actin nucleator; modulation of actin-mediated changes involved in host cell invasion, and of host cell survival. | [158, 170, 175–178, 186, 190] |
| CT473 | CTL0734 | Lda3 | Secretion: unknown; targets: unknown; localization: around the inclusion, overlapping with LD-like structures; function: targeting and modulation of LDs. | [54, 219, 220] |
| CT529 | CTL0791 | Cap1 | Secretion: T3S; targets: unknown; localization: inclusion membrane; function: associates with LDs. | [50, 63, 221, 280] |
| CT620 | CTL0884 | - | Secretion: T3S; targets: Hrs/ESCRT machinery; localization: inclusion lumen, cytosol and nucleus; function: unknown. | [212, 214] |
| CT621 | CTL0885 | - | Secretion: T3S; targets: Hrs/ESCRT machinery; localization: inclusion lumen, cytosol and nucleus; function: unknown. | [212–214] |
| CT622 | CTL0886 | - | Secretion: T3S; targets: unknown; localization: inclusion lumen and cytosol; function: involved in bacterial infectivity and growth; structural similarities with GGTases and synthases. | [200, 201] |
| CT694 | CTL0063 | TmeA | Secretion: T3S; targets: AHNAK; localization: cytosol, near the nascent inclusion, and host cell plasma membrane; function: involved in host cell invasion. | [185, 186, 189–191] |
| CT695 | CTL0064 | TmeB | Secretion: T3S; targets: unknown; localization: cytosol, near the nascent inclusion, and inclusion membrane; function: unknown. | [185, 186] |
| CT711 | CTL0080 | - | Secretion: T3S; targets: Hrs/ESCRT machinery; localization: nucleus; function: unknown. | [212, 214] |
| CT737 | CTL0106 | NUE | Secretion: T3S; targets: histones H2B, H3 and H4; localization: nucleus; function: histone methyltransferase. | [226] |
| CT795 | CTL0164 | - | Secretion: Sec-dependent/T2S; targets: unknown; localization: inclusion lumen and cytosol; function: unknown. | [278] |
| CT798 | CTL0167 | GlgA | Secretion: T3S; targets: N/A; localization: inclusion lumen and cytosol; function: glycogen synthase. | [288] |
| CT806 | CTL0175 | Ptr | Secretion: Sec-dependent/T2S; targets: N/A; localization: inclusion lumen; function: putative protease involved in recovery of C. trachomatis from IFN?-induced stress. | [292] |
| CT823 | CTL0195 | HtrA | Secretion: Sec-dependent/T2S; targets: unknown; localization: inclusion lumen and cytosol; function: serine protease with roles in the chlamydial periplasm, but unknown function in the host cell cytosol. | [261, 262] |
| CT858 | CTL0233 | CPAF | Secretion: Sec-dependent/T2S; targets: several, but many shown to be experimental artifacts; localization: inclusion lumen and cytosol; function: promotion of chlamydial survival in the mouse lower genital tract; evasion of innate immune responses; chlamydial lytic exit; inhibition of host cell cytokinesis; inhibition of p65 nuclear translocation (based on phenotypes displayed by cpaf mutant C. trachomatis). | [231, 232, 234–237, 240, 241, 245, 248, 250–252, 255] |
| CT867 | CTL0246 | ChlaDUB2 /Cdu2 | Secretion: unknown; targets: unknown; localization: inclusion membrane and host cell plasma membrane; function: DUB and deneddylase activities; contributes to Golgi redistribution around the inclusion. | [189, 204, 206] |
| CT868 | CTL0247 | ChlaDUB1/ Cdu1 | Secretion: unknown; targets: MCL1, I?B?; localization: inclusion membrane; function: DUB, deneddylase and acetyl transferase activities; contributes to Golgi redistribution around the inclusion; inhibition of NF-?B signalling and of host cell death. | [11, 189, 204, 206, 209] |
| CT875 | CTL0255 | TepP | Secretion: T3S; targets: CRK, CRKL, PI3K subunits, and GSK3B; localization: cytosol, near the early vacuole; function: modulation of host gene expression related with immune signalling in early stages of infection. | [195, 196] |
| pGP3/pORF5 | Secretion: unknown; targets: cathelicidin LL-37 (antimicrobial peptide); localization: inclusion lumen and cytosol; function: neutralization of the LL-37activity, evasion of the acidic barrier in the vagina, modulation of inflammatory responses, inhibition of host cell apoptosis. | [268, 274–277] | ||
a
Only C. trachomatis proteins reported to be experimentally detected in the inclusion membrane, inclusion lumen, host cell cytoplasm or nucleus are listed. In addition, there is functional evidence for secretion and effector role of CT166 (Chlamydia cytotoxin targeting RAC1 that might contribute for downmodulating actin cytoskeleton changes during chlamydial invasion of host cells [197, 199]), CT619/CTL0883 and CT712/CTL0081 (as CT620/CTL0884, CT621/CTL0885, and CT711/CTL0080, listed in Table 2, these two proteins contain the Chlamydiacea-unique DUF582 domain and bind components of the ESCRT machinery [212, 214]), and CT847/CTL0217 (binds GCIP [229]) in the host cell cytoplasm, and of GlgB, GlgP, MalQ and MrsA in the inclusion lumen [14, 289]. See list of abbreviations and main text for abbreviations and protein nomenclature, respectively.