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Pre-protein VI



Human adenovirus C serotype 5 (HAdV-5) (Human adenovirus 5)
Reviewed-Annotation score: -Experimental evidence at protein leveli


Pre-protein VI: During virus assembly, promotes hexon trimers nuclear import through nuclear pore complexes via an importin alpha/beta-dependent mechanism. By analogy to herpesviruses capsid assembly, might act as a chaperone to promote the formation of the icosahedral capsid.UniRule annotation1 Publication
Endosome lysis protein: Structural component of the virion that provides increased stability to the particle shell through its interaction with the core-capsid bridging protein and the hexon-linking protein VIII (PubMed:25071205). Fibers shedding during virus entry into host cell allows the endosome lysis protein to be exposed as a membrane-lytic peptide (By similarity). Exhibits pH-independent membrane fragmentation activity and probably mediates viral rapid escape from host endosome via organellar membrane lysis (PubMed:15681401, PubMed:21209115, PubMed:20409568, PubMed:22516138). It is not clear if it then remains partially associated with the capsid and involved in the intracellular microtubule-dependent transport of capsid to the nucleus, or if it is lost during endosomal penetration (PubMed:20333243).UniRule annotationBy similarity6 Publications
Protease cofactor: Cofactor that activates the viral protease. Binds to viral protease in a 1:1 ratio.UniRule annotation


All late proteins expressed from the major late promoter are produced by alternative splicing and alternative polyadenylation of the same gene giving rise to non-overlapping ORFs. A leader sequence is present in the N-terminus of all these mRNAs and is recognized by the viral shutoff protein to provide expression although conventional translation via ribosome scanning from the cap has been shut off in the host cell.UniRule annotation

GO - Biological processi


Biological processCytoplasmic inwards viral transport, Host-virus interaction, Microtubular inwards viral transport, Viral capsid assembly, Viral penetration into host cytoplasm, Viral penetration via lysis of host organellar membrane, Viral release from host cell, Virus entry into host cell

Names & Taxonomyi

Protein namesi
Recommended name:
Pre-protein VIUniRule annotation
Short name:
pVIUniRule annotation
Cleaved into the following 2 chains:
Endosome lysis proteinUniRule annotation
Protease cofactorUniRule annotation
Alternative name(s):
pVI-CUniRule annotation
Gene namesi
Name:L3UniRule annotation
OrganismiHuman adenovirus C serotype 5 (HAdV-5) (Human adenovirus 5)
Taxonomic identifieri28285 [NCBI]
Taxonomic lineageiVirusesdsDNA viruses, no RNA stageAdenoviridaeMastadenovirus
Virus hostiHomo sapiens (Human) [TaxID: 9606]
  • UP000004992 Componenti: Genome

Subcellular locationi

Pre-protein VI :
Endosome lysis protein :
  • Virion UniRule annotation1 Publication
  • Note: Associates with the base of each peripentonal hexon on the capsid interior. Present in around 360 copies per virion.UniRule annotation1 Publication

GO - Cellular componenti

Keywords - Cellular componenti

Capsid protein, Host cytoplasm, Host nucleus, Virion

Pathology & Biotechi


Feature keyPosition(s)DescriptionActionsGraphical viewLength
Mutagenesisi40L → Q: Impaired endosome penetration and reduces infectivity. 1 Publication1
Mutagenesisi48G → C: Decreased infectivity and endosomal membrane disruption activity. 1 Publication1
Mutagenesisi149 – 151PSY → GAA: No effect on endosomal escape; defective in microtubule-dependent trafficking toward the nucleus. 1 Publication3

PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
ChainiPRO_00004211331 – 250Pre-protein VIUniRule annotationAdd BLAST250
PropeptideiPRO_00000365461 – 33UniRule annotationAdd BLAST33
ChainiPRO_000003654734 – 239Endosome lysis proteinUniRule annotationAdd BLAST206
ChainiPRO_0000439553240 – 250Protease cofactorUniRule annotationAdd BLAST11
PeptideiPRO_0000036548240 – 250Protease cofactorAdd BLAST11

Amino acid modifications

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Modified residuei124Phosphoserine; by hostUniRule annotation1
Modified residuei143Phosphothreonine; by hostUniRule annotation1
Disulfide bondi249Interchain (with Adenovirus protease)UniRule annotation

Post-translational modificationi

Ubiquitinated by Nedd4 following partial capsid disassembly; which might play a role in intracellular virus movement during entry.UniRule annotation1 Publication
Protease cofactor: Contains the major nuclear import and export signals. Proteolytically removed during virion maturation. The processing of the C-terminus turns the precursor into a mature viral structural protein and abrogates its ability to promote hexon import and act as a potential chaperone protein.UniRule annotation1 Publication


Feature keyPosition(s)DescriptionActionsGraphical viewLength
Sitei33 – 34Cleavage; by viral proteaseUniRule annotation2
Sitei239 – 240Cleavage; by viral proteaseUniRule annotation2

Keywords - PTMi

Disulfide bond, Phosphoprotein, Ubl conjugation

Miscellaneous databases




Expressed in the late phase of the viral replicative cycle.UniRule annotation

Keywords - Developmental stagei

Late protein


Subunit structurei

Pre-protein VI: Interacts with hexon protein; this interaction allows nuclear import of hexon trimers and possibly pre-capsid assembly (PubMed:14633984). Pre-protein VI: Interacts (via C-terminal NLS) with importin alpha/beta (PubMed:14633984). Endosome lysis protein: Interacts (via PPxY motif) with host NEDD4 ubiquitine ligase; this interaction might play a role in virus intracellular transport during entry (PubMed:20333243). Endosome lysis protein: Part of a complex composed of the core-capsid bridging protein, the endosome lysis protein VI and the hexon-linking protein VIII; these interactions bridge the virus core to the capsid (PubMed:25071205). Endosome lysis protein: Interacts with peripentonal hexons; this interaction stabilizes the capsid by gluing two peripentonal hexons together and joining them with an adjacent group-of-nine hexon (PubMed:25071205). Protease cofactor: Heterodimer with the viral protease; disulfide-linked (By similarity). Interacts with the viral protease (By similarity).UniRule annotationBy similarity3 Publications


3D structure databases


Miscellaneous databases


Family & Domainsi


Feature keyPosition(s)DescriptionActionsGraphical viewLength
Regioni34 – 54Amphipathic alpha-helix essential for membrane lytic activityUniRule annotationAdd BLAST21
Regioni36 – 53Involved in endosomal membrane lysisUniRule annotationAdd BLAST18
Regioni48 – 74Interaction with hexon proteinUniRule annotationAdd BLAST27
Regioni105 – 225DisorderedUniRule annotationAdd BLAST121
Regioni233 – 239Interaction with hexon proteinUniRule annotation7
Regioni240 – 250Binds to importin alpha/beta, involved in hexon nuclear importUniRule annotationAdd BLAST11


Feature keyPosition(s)DescriptionActionsGraphical viewLength
Motifi67 – 76Nuclear export signalUniRule annotation10
Motifi131 – 135Nuclear localization signalUniRule annotation5
Motifi148 – 151PPXY motifUniRule annotation4
Motifi231 – 242Nuclear export signalUniRule annotationAdd BLAST12
Motifi245 – 248Nuclear localization signalUniRule annotation4


N-terminal amphipathic alpha-helix domain is essential for the membrane lytic activity.UniRule annotation1 Publication
Late-budding domains (L domains) are short sequence motifs essential for viral particle release. They can occur individually or in close proximity within structural proteins. They interacts with sorting cellular proteins of the multivesicular body (MVB) pathway. Most of these proteins are class E vacuolar protein sorting factors belonging to ESCRT-I, ESCRT-II or ESCRT-III complexes. Minor capsid protein 6 contains one L domain: a PPXY motif which binds to the WW domains of HECT (homologous to E6-AP C-terminus) E3 ubiquitin ligases, like NEDD4. In adenoviruses, this motif seems to play a role in microtubule-dependent intracellular trafficking toward the nucleus during virus entry into host cell and in suppression of DAXX-mediated repression of the immediate early E1A promoter.UniRule annotation1 Publication

Sequence similaritiesi

Belongs to the adenoviridae protein VI family.UniRule annotationCurated

Phylogenomic databases


Family and domain databases

HAMAPiMF_04048 ADV_CAP6, 1 hit
InterProiView protein in InterPro
IPR004243 McpVI
PfamiView protein in Pfam
PF02993 MCPVI, 1 hit


Sequence statusi: Complete.

Sequence processingi: The displayed sequence is further processed into a mature form.

P24937-1 [UniParc]FASTAAdd to basket
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Mass (Da):26,996
Last modified:March 1, 1992 - v1

Sequence databases

Select the link destinations:
Links Updated
M73260 Genomic DNA Translation: AAA96411.1
PIRiD39449 Q5ADB5
RefSeqiAP_000210.1, AC_000008.1

Similar proteinsi

Entry informationi

Entry nameiCAP6_ADE05
AccessioniPrimary (citable) accession number: P24937
Entry historyiIntegrated into UniProtKB/Swiss-Prot: March 1, 1992
Last sequence update: March 1, 1992
Last modified: June 20, 2018
This is version 92 of the entry and version 1 of the sequence. See complete history.
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programViral Protein Annotation Program


Keywords - Technical termi

3D-structure, Complete proteome, Reference proteome
UniProt is an ELIXIR core data resource
Main funding by: National Institutes of Health

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