Literature summary for 7.4.2.14 extracted from

Russ, G.; Esquivel, F.; Yewdell, J.; Cresswell, P.; Spies, T.; Bennink, J.
Assembly, intracellular localization, and nucleotide binding properties of the human peptide transporters TAP1 and TAP2 expressed by recombinant vaccinia viruses (1995), J. Biol. Chem., 270, 21312-21318 .

Search for more literature for 7.4.2.14

Cloned(Commentary)

Cloned (Comment)	Organism
human TAP1 (a allotype) and TAP2 (b allotype) genes, recombinant expression using Vaccinia virus (VV) constructs (rVVs encoding A/Puerto Rico/8/34 influenza virus HA and NP under the control of the VV p7.5 promoter) and human T2 an B6 cells, which are deficient for antigen processing, or murine L929 fibroblasts. VV-expressed TAP1 and TAP2 are functional, but only when expressed together	Homo sapiens

Protein Variants

Protein Variants	Comment	Organism
additional information	production of recombinant vaccinia viruses that direct synthesis of the TAP subunits, either individually or together. Virus-encoded TAP is rapidly and efficiently assembles (t1/2 of 5 min or less) by cells and does not spontaneously assemble in detergent extracts. Metabolic labeling with [2-3H]mannose demonstrates that TAP1 (but not TAP2) possesses Asn-linked oligosaccharides, but the lack of binding of [35S]methionine-labeled TAP to concanavalin A-agarose suggests that the glycosylated form represents a minor population of TAP1. The two subunits of the assembled complex present in detergent extracts photolabeled equally with 8-azido-[alpha-32P]ATP. Photolabeling of the two subunits is inhibited in parallel by various di- and trinucleotides, suggesting that their nucleotide binding sites function in a highly similar manner	Homo sapiens

General Stability

General Stability	Organism
incubation of detergent extracts at 37°C results in the rapid loss of TAP1 immunoreactivity, indicating either an unusual sensitivity to proteases or an irreversible conformation alteration	Homo sapiens

Inhibitors

Inhibitors	Comment	Organism	Structure
EDTA	complete inhibition, addition of excess Mg2+ to EDTA-containing samples restores labeling	Homo sapiens
additional information	incubation of detergent extracts at 37°C results in the rapid loss of TAP1 immunoreactivity, indicating either an unusual sensitivity to proteases or an irreversible conformation alteration	Homo sapiens
Nonidet P-40	-	Homo sapiens
Triton-X 100	-	Homo sapiens

Localization

Localization	Comment	Organism	GeneOntology No.	Textmining
endoplasmic reticulum membrane	TAP1 when expressed alone or with TAP2 is largely, if not exclusively, localized to the endoplasmic reticulum, confocal immunofluorescence microscopy. Immunofluorescence localization study of recombinant TAP in VV-TAP[112]-infected murine L929 cells	Homo sapiens	5789	-

Metals/Ions

Metals/Ions	Comment	Organism	Structure
Ca2+	activates	Homo sapiens
Mg2+	required	Homo sapiens
additional information	the enhanced ATP binding observed when Mg2+ is supplemented with Ca21 is consistent with two possibilities: (1) the cytosolic domains possess a Ca2+ binding site in addition to the Mg2+ binding site, and (2) additional Ca2+-dependent factors in the extract contribute to ATP binding to TAP	Homo sapiens

Natural Substrates/ Products (Substrates)

Natural Substrates	Organism	Comment (Nat. Sub.)	Natural Products	Comment (Nat. Pro.)	Rev.	Reac.
ATP + H2O + antigen peptide[side 1]	Homo sapiens	-	ADP + phosphate + antigen peptide[side 2]	-	?
GTP + H2O + antigen peptide[side 1]	Homo sapiens	less than 40% activity compared to ATP	GDP + phosphate + antigen peptide[side 2]	-	?

Organism

Organism	UniProt	Comment	Textmining
Homo sapiens	Q03518 AND Q03519	TAP1 and TAP2 subunits	-

Posttranslational Modification

Posttranslational Modification	Comment	Organism
glycoprotein	metabolic labeling with [2-3H]mannose demonstrates that TAP1 (but not TAP2) possesses Asn-linked oligosaccharides, but the lack of binding of [35S]methionine-labeled TAP to concanavalin A-agarose suggests that the glycosylated form represents a minor population of TAP1	Homo sapiens

Substrates and Products (Substrate)

Substrates	Comment Substrates	Organism	Products	Comment (Products)	Rev.	Reac.
ATP + H2O + antigen peptide[side 1]	-	Homo sapiens	ADP + phosphate + antigen peptide[side 2]	-	?
GTP + H2O + antigen peptide[side 1]	less than 40% activity compared to ATP	Homo sapiens	GDP + phosphate + antigen peptide[side 2]	-	?
additional information	no activity with CTP and UTP	Homo sapiens	?	-	-

Synonyms

Synonyms	Comment	Organism
peptide transporter	-	Homo sapiens
TAP	-	Homo sapiens
TAP1	-	Homo sapiens
TAP2	-	Homo sapiens
transporter associated with antigen processing	-	Homo sapiens

Temperature Optimum [°C]

Temperature Optimum [°C]	Temperature Optimum Maximum [°C]	Comment	Organism
37	-	assay at	Homo sapiens

pH Optimum

pH Optimum Minimum	pH Optimum Maximum	Comment	Organism
7.4	-	assay at	Homo sapiens

Cofactor

Cofactor	Comment	Organism	Structure
ATP	-	Homo sapiens
GTP	it is likely that GTP also serves as a TAP ligand in vivo	Homo sapiens
additional information	TAP1 and TAP2 enzyme binding studies using 8-azido-[a-32P]ATP, revealing labeling of both TAP subunits, overview	Homo sapiens

General Information

General Information	Comment	Organism
evolution	TAP1 and TAP2 are members of the ABC transporter family	Homo sapiens
additional information	the two subunits of the assembled complex present in detergent extracts photolabeled equally with 8-azido-[alpha-32P]ATP. Photolabeling of the two subunits is inhibited in parallel by various di- and trinucleotides, suggesting that their nucleotide binding sites function in a highly similar manner	Homo sapiens
physiological function	the transporter associated with antigen processing (TAP) transports short peptides from the cytosol to the endoplasmic reticulum, where peptides assemble with class I molecules of the major histocompatibility complex. TAP is comprised of two subunits, termed TAP1 and TAP2	Homo sapiens

Use of this online version of BRENDA is free under the CC BY 4.0 license. See terms of use for full details.

Release 2023.1 (January 2023)