AC   MF_04048;
DC   Protein; auto
TR   HAMAP; MF_04048; -; 1; level=0
XX
Names: ADV_CAP6
XX
ID   CAP6
DE   RecName: Full=Pre-protein VI;
DE            Short=pVI;
DE   Contains:
DE     RecName: Full=Endosome lysis protein;
DE   Contains:
DE     RecName: Full=Protease cofactor;
DE     AltName: Full=pVI-C;
GN   Name=L3;
XX
CC   -!- FUNCTION: Pre-protein VI: During virus assembly, promotes hexon trimers
CC       nuclear import through nuclear pore complexes via an importin
CC       alpha/beta-dependent mechanism. By analogy to herpesviruses capsid
CC       assembly, might act as a chaperone to promote the formation of the
CC       icosahedral capsid.
CC   -!- FUNCTION: Endosome lysis protein: Structural component of the virion
CC       that provides increased stability to the particle shell through its
CC       interaction with the core-capsid bridging protein and the hexon-linking
CC       protein VIII. Fibers shedding during virus entry into host cell allows
CC       the endosome lysis protein to be exposed as a membrane-lytic peptide.
CC       Exhibits pH-independent membrane fragmentation activity and probably
CC       mediates viral rapid escape from host endosome via organellar membrane
CC       lysis. It is not clear if it then remains partially associated with the
CC       capsid and involved in the intracellular microtubule-dependent
CC       transport of capsid to the nucleus, or if it is lost during endosomal
CC       penetration.
CC   -!- FUNCTION: Protease cofactor: Cofactor that activates the viral
CC       protease. Binds to viral protease in a 1:1 ratio.
CC   -!- SUBUNIT: [Pre-protein VI]: Interacts with hexon protein; this
CC       interaction allows nuclear import of hexon trimers and possibly pre-
CC       capsid assembly. Interacts (via C-terminal NLS) with importin
CC       alpha/beta.
CC   -!- SUBUNIT: [Endosome lysis protein]: Interacts (via PPxY motif) with host
CC       NEDD4 ubiquitine ligase; this interaction might play a role in virus
CC       intracellular transport during entry. Part of a complex composed of the
CC       core-capsid bridging protein, the endosome lysis protein VI and the
CC       hexon-linking protein VIII; these interactions bridge the virus core to
CC       the capsid. Interacts with peripentonal hexons; this interaction
CC       stabilizes the capsid by gluing two peripentonal hexons together and
CC       joining them with an adjacent group-of-nine hexon.
CC   -!- SUBUNIT: [Protease cofactor]: Heterodimer with the viral protease;
CC       disulfide-linked. Interacts with the viral protease.
CC   -!- SUBCELLULAR LOCATION: Pre-protein VI: Host nucleus. Host cytoplasm.
CC       Note=Shuttles between host cytoplasm and nucleus.
CC   -!- SUBCELLULAR LOCATION: Endosome lysis protein: Virion. Note=Associates
CC       with the base of each peripentonal hexon on the capsid interior.
CC       Present in around 360 copies per virion.
CC   -!- INDUCTION: Expressed in the late phase of the viral replicative cycle.
CC   -!- DOMAIN: N-terminal amphipathic alpha-helix domain is essential for the
CC       membrane lytic activity.
CC   -!- DOMAIN: Late-budding domains (L domains) are short sequence motifs
CC       essential for viral particle release. They can occur individually or in
CC       close proximity within structural proteins. They interacts with sorting
CC       cellular proteins of the multivesicular body (MVB) pathway. Most of
CC       these proteins are class E vacuolar protein sorting factors belonging
CC       to ESCRT-I, ESCRT-II or ESCRT-III complexes. Minor capsid protein 6
CC       contains one L domain: a PPXY motif which binds to the WW domains of
CC       HECT (homologous to E6-AP C-terminus) E3 ubiquitin ligases, like NEDD4.
CC       In adenoviruses, this motif seems to play a role in microtubule-
CC       dependent intracellular trafficking toward the nucleus during virus
CC       entry into host cell and in suppression of DAXX-mediated repression of
CC       the immediate early E1A promoter.
CC   -!- PTM: Ubiquitinated by Nedd4 following partial capsid disassembly; which
CC       might play a role in intracellular virus movement during entry.
CC   -!- PTM: Protease cofactor: Contains the major nuclear import and export
CC       signals. Proteolytically removed during virion maturation. The
CC       processing of the C-terminus turns the precursor into a mature viral
CC       structural protein and abrogates its ability to promote hexon import
CC       and act as a potential chaperone protein.
CC   -!- MISCELLANEOUS: All late proteins expressed from the major late promoter
CC       are produced by alternative splicing and alternative polyadenylation of
CC       the same gene giving rise to non-overlapping ORFs. A leader sequence is
CC       present in the N-terminus of all these mRNAs and is recognized by the
CC       viral shutoff protein to provide expression although conventional
CC       translation via ribosome scanning from the cap has been shut off in the
CC       host cell.
CC   -!- SIMILARITY: Belongs to the adenoviridae protein VI family.
XX
DR   Pfam; PF02993; MCPVI; 1; trigger=no
XX
KW   Capsid protein
KW   Cytoplasmic inwards viral transport
KW   Disulfide bond
KW   Host cytoplasm
KW   Host nucleus
KW   Host-virus interaction
KW   Late protein
KW   Microtubular inwards viral transport
KW   Phosphoprotein
KW   Ubl conjugation
KW   Viral capsid assembly
KW   Viral penetration into host cytoplasm
KW   Viral penetration via lysis of host organellar membrane
KW   Virion
KW   Virus entry into host cell
KW   Viral release from host cell
XX
GO   GO:0030430; C:host cell cytoplasm
GO   GO:0042025; C:host cell nucleus
GO   GO:0019028; C:viral capsid
GO   GO:0046729; C:viral procapsid
GO   GO:0039664; P:lysis of host organelle involved in viral entry into host cell
GO   GO:0075521; P:microtubule-dependent intracellular transport of viral material towards nucleus
GO   GO:0019076; P:viral release from host cell
XX
FT   From: CAP6_ADE05 (P24937)
FT   CHAIN           Nter..Cter
FT                   /note="Pre-protein VI"
FT   PROPEP          Nter..33
FT   CHAIN           34..239
FT                   /note="Endosome lysis protein"
FT   CHAIN           240..250
FT                   /note="Protease cofactor"
FT   REGION          34..54
FT                   /note="Amphipathic alpha-helix essential for membrane lytic
FT                   activity"
FT   REGION          36..53
FT                   /note="Involved in endosomal membrane lysis"
FT   REGION          48..74
FT                   /note="Interaction with hexon protein"
FT   REGION          233..239
FT                   /note="Interaction with hexon protein"
FT   REGION          240..250
FT                   /note="Binds to importin alpha/beta, involved in hexon
FT                   nuclear import"
FT   MOTIF           67..76
FT                   /note="Nuclear export signal"
FT   MOTIF           131..135
FT                   /note="Nuclear localization signal"
FT   Condition: [KR]-[KR]-x-[KR]-x
FT   MOTIF           148..151
FT                   /note="PPXY motif"
FT   Condition: P-P-x-Y
FT   MOTIF           231..242
FT                   /note="Nuclear export signal"
FT   MOTIF           245..248
FT                   /note="Nuclear localization signal"
FT   Condition: [KR]-[KR]-[KR]-[KR]
FT   SITE            33..34
FT                   /note="Cleavage; by viral protease"
FT   SITE            239..240
FT                   /note="Cleavage; by viral protease"
FT   MOD_RES         124
FT                   /note="Phosphoserine; by host"
FT   Condition: S
FT   MOD_RES         143
FT                   /note="Phosphothreonine; by host"
FT   Condition: T
FT   DISULFID        249
FT                   /note="Interchain (with Adenovirus protease)"
FT   Condition: C
XX
Size: 223-267;
Related: None;
Template: P24937;
Scope:
 Viruses; Adenoviridae
Fusion:
 Nter: None
 Cter: None
Duplicate: None
Plasmid: None
Comments: None
XX
# Revision 1.9 2021/10/15
//