Hop (protein)

STIP1
Available structures PDB Ortholog search: PDBe RCSB List of PDB id codes 1ELR, 1ELW, 2LNI, 3ESK, 3FWV
Identifiers
Aliases	STIP1, HEL-S-94n, HOP, IEF-SSP-3521, P60, STI1, STI1L, stress induced phosphoprotein 1
External IDs	OMIM: 605063; MGI: 109130; HomoloGene: 4965; GeneCards: STIP1; OMA:STIP1 - orthologs
Gene location (Human) Chr. Chromosome 11 (human) Band 11q13.1 Start 64,185,272 bp End 64,204,543 bp
Gene location (Mouse) Chr. Chromosome 19 (mouse) Band 19|19 A Start 6,998,070 bp End 7,017,335 bp
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in ganglionic eminence islet of Langerhans right adrenal gland left adrenal gland stromal cell of endometrium right uterine tube anterior pituitary gastrocnemius muscle prefrontal cortex smooth muscle tissue Top expressed in morula yolk sac neural tube abdominal wall superior frontal gyrus primitive streak thymus ganglionic eminence somite medial vestibular nucleus More reference expression data BioGPS More reference expression data
Gene ontology Molecular function Hsp70 protein binding protein C-terminus binding chaperone binding protein binding RNA binding Hsp90 protein binding Cellular component cytoplasm myelin sheath Golgi apparatus nucleus cytosol protein-containing complex chaperone complex Biological process response to stress cellular response to interleukin-7 Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 10963 20867 Ensembl ENSG00000168439 ENSMUSG00000024966 UniProt P31948 Q60864 RefSeq (mRNA) NM_006819 NM_001282652 NM_001282653 NM_016737 RefSeq (protein) NP_001269581 NP_001269582 NP_006810 NP_058017 Location (UCSC) Chr 11: 64.19 – 64.2 Mb Chr 19: 7 – 7.02 Mb PubMed search
Wikidata
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Hop (occasionally HOP) is the Hsp70-Hsp90 organizing protein. It functions as a co-chaperone which reversibly links together the protein chaperones Hsp70 and Hsp90. Template:PBB Summary

Synonym protein names

Hop Hsc70/Hsp90-organizing protein NY-REN-11 antigen P60

STI1 STI1L STIP1 Transformation-sensitive protein IEF-SSP-3521

Introduction

HOP (the abbrevation stands for Hsp70/Hsp90 Organizing Protein) belongs to the large group of co-chaperones, which regulate and assist the major chaperones (mainly heat shock proteins). It is one of the best studied co-chaperones of the Hsp70/Hsp90-complex. It was first discovered in yeast and homologues were identified in human, mouse, rat, insects, plants, parasites, and virus. The family of these proteins is referred to as STI1 (stress inducible protein) and can be divided into yeast, plant, and animal STI1 (Hop).

Gene name and Structure

The gene for human Hop is located on chromosome 11q13.1 and consists of 14 exons.

STI proteins are characterized by some structural features: All homologues have nine tetratricopeptide repeat (TPR) motifs, that are clustered into domains of three TPRs. The TPR motif is a very common structural feature used by many proteins and provides the ability of directing protein-protein interactions. Crystallographic structural information is available for the N-terminal TPR1 and the central TPR2A domains in complex with Hsp90 resp. Hsp70 ligand peptides.

Function

The main function of Hop is to link Hsp70 and Hsp90 together. But recent investigations indicate that it also modulates the chaperone activities of the linked proteins and possibly interacts with other chaperones and proteins. Apart from its role in the Hsp70/Hsp90 "chaperone machine" it seems to participate in other protein complexes too (for example in the signal transduction complex EcR/USP and in the Hepatitis B virus reverse transcriptase complex, which enables the viral replication). It acts as a receptor for prion proteins too. Hop is located in diverse cellular regions and also moves between the cytoplasm and the nucleus.

See also

• chaperones
• heat shock proteins
• Hsp70
• hsp90

Sources

This article is mainly based on this review:

Odunuga OO, Longshaw VM,and Blatch GL. BioEssays 26:1058–1068, 2004.