Inhibition of immunoglobulin folding and secretion by dominant negative BiP ATPase mutants.

Hendershot, Linda M.; Wei, Jie; Gaut, James R.; Melnick, Jeffrey; Aviel, S; Argon, Yair

doi:10.1073/pnas.93.11.5269

Cited by 144 publications

(142 citation statements)

References 39 publications

Supporting

Mentioning

131

Contrasting

Unclassified

Order By: Relevance

“…In vivo, it is assumed that ATP must rebind to the nucleotide-binding cleft to allow release of bound proteins at the appropriate time so they can fold. This hypothesis is supported by data obtained with BiP ATP-binding mutants showing that the mutants prevent the folding of bound substrates but keep them in a soluble form (37). The in vitro addition of ATP to complexes induces the release of BiP, which can provide an opportunity for the substrate to fold or in some cases leads 3 J. L. Brodsky, personal communication.…”

Section: Discussionsupporting

confidence: 62%

BAP, a Mammalian BiP-associated Protein, Is a Nucleotide Exchange Factor That Regulates the ATPase Activity of BiP

Chung

Shen

Hendershot

2002

Journal of Biological Chemistry

166

121

View full text Add to dashboard Cite

We identified a mammalian BiP-associated protein, BAP, using a yeast two-hybrid screen that shared low homology with yeast Sls1p/Sil1p and mammalian HspBP1, both of which regulate the ATPase activity of their Hsp70 partner. BAP encoded an ϳ54-kDa protein with an N-terminal endoplasmic reticulum (ER) targeting sequence, two sites of N-linked glycosylation, and a C-terminal ER retention sequence. Immunofluorescence staining demonstrated that BAP co-localized with GRP94 in the endoplasmic reticulum. BAP was ubiquitously expressed but showed the highest levels of expression in secretory organ tissues, a pattern similar to that observed with BiP. BAP binding was affected by the conformation of the ATPase domain of BiP based on in vivo binding studies with BiP mutants. BAP stimulated the ATPase activity of BiP when added alone or together with the ER DnaJ protein, ERdj4, by promoting the release of ADP from BiP. Together, these data demonstrate that BAP serves as a nucleotide exchange factor for BiP and provide insights into the mechanisms that control protein folding in the mammalian ER.

show abstract

Section: Discussionsupporting

confidence: 62%

BAP, a Mammalian BiP-associated Protein, Is a Nucleotide Exchange Factor That Regulates the ATPase Activity of BiP

Chung

Shen

Hendershot

2002

Journal of Biological Chemistry

166

121

View full text Add to dashboard Cite

show abstract

“…A vector that encodes Chinese hamster BiP has previously been described (21). For immunofluorescence (22), transfected cells grown on coverslips were fixed and stained with an anti-HA antibody to detect ssYdj1 followed by fluorescein isothiocyanate-labeled secondary antibody.…”

Section: Methodsmentioning

confidence: 99%

The Mammalian Hsp40 ERdj3 Requires Its Hsp70 Interaction and Substrate-binding Properties to Complement Various Yeast Hsp40-dependent Functions

Vembar

Jin

Brodsky

et al. 2009

Journal of Biological Chemistry

View full text Add to dashboard Cite

Heat shock proteins of 70 kDa (Hsp70s) and their J domaincontaining Hsp40 cofactors are highly conserved chaperone pairs that facilitate a large number of cellular processes. The observation that each Hsp70 partners with many J domain-containing proteins (JDPs) has led to the hypothesis that Hsp70 function is dictated by cognate JDPs. If this is true, one might expect highly divergent Hsp70-JDP pairs to be unable to function in vivo. However, we discovered that, when a yeast cytosolic JDP, Ydj1, was targeted to the mammalian endoplasmic reticulum (ER), it interacted with the ER-lumenal Hsp70, BiP, and bound to BiP substrates. Conversely, when a mammalian ERlumenal JDP, ERdj3, was directed to the yeast cytosol, it rescued the temperature-sensitive growth phenotype of yeast-containing mutant alleles in two cytosolic JDPs, HLJ1 and YDJ1, and activated the ATP hydrolysis rate of Ssa1, the yeast cytosolic Hsp70 that partners with Hlj1 and Ydj1. Surprisingly, ERdj3 mutants that were compromised for substrate binding were unable to rescue the hlj1ydj1 growth defect even though they stimulated the ATPase activity of Ssa1. Yet, J domain mutants of ERdj3 that were defective for interaction with Ssa1 restored the growth of hlj1ydj1 yeast. Taken together, these data suggest that the substrate binding properties of certain JDPs, not simply the formation of unique Hsp70-JDP pairs, are critical to specify in vivo function. Hsp70s3 constitute a highly conserved family of molecular chaperones that are found in all organisms and in all cellular organelles. Due to their ability to bind to unfolded regions on nascent polypeptides or unassembled subunits of heteromeric complexes in a nucleotide-dependent manner, these chaperones play critical roles in diverse cellular processes (1, 2). Two distinct sets of cofactors tightly monitor Hsp70 action by regulating ATPase activity (3, 4): J domain-containing proteins (JDPs) of the Hsp40/DnaJ family and nucleotide exchange factors. The highly conserved ϳ70-amino acid J domain of JDPs contacts the nucleotide-binding domain of Hsp70 and enhances ATPase activity by inducing a conformational change (5, 6). This leads to enhanced binding of Hsp70s to substrates. Moreover, some JDPs directly bind to unfolded regions on substrate proteins through their substrate-binding domain and deliver the unfolded protein to the ATP-bound form of their Hsp70 partner (7, 8), whereas others contain atypical domains that specify exclusive functions (9, 10). The nucleotide exchange factors, on the other hand, release bound ADP, which triggers ATP rebinding and subsequent substrate release from the Hsp70.The JDPs can be classified into three groups (11, 12): (i) type I JDPs are most similar to DnaJ and contain a J domain followed by a glycine/phenylalanine-rich region and a cysteine-rich region with four repeats of a CXXCXGXG-type zinc finger; (ii) type II JDPs lack the cysteine-rich region and are unable to coordinate Zn 2ϩ ; and (iii) type III JDPs only have the J domain in common with DnaJ. Notably, the number o...

show abstract

“…The endoplasmic reticulum resident chaperones BiP and GRP94 associate with both secreted and nonsecreted Ig proteins (16,(31)(32)(33). We have shown that the low secretor H chains have an increased association with these chaperones as compared with the secretion-competent wtT15H chain when coexpressed with the wtT15L chain (8).…”

Section: Secretion-restoring L Chain Mutations Restore H Chain Secretionmentioning

confidence: 99%

Restoration of Ig Secretion: Mutation of Germline-Encoded Residues in T15L Chains Leads to Secretion of Free Light Chains and Assembled Antibody Complexes Bearing Secretion-Impaired Heavy Chains

Whitcomb

Martin

Rittenberg

2003

The Journal of Immunology

View full text Add to dashboard Cite

We previously described T15H chain mutants that were impaired in assembly with L chain and in ability to be secreted from the cell. The unmutated T15L chain is unusual in that it is secretion-impaired in the absence of assembly with H chain. The T15L chain preferentially pairs with T15H in vivo, suggesting that if we introduced mutations that would allow secretion of free T15L chain, they might also lead to the secretion of the complex with the defective H chain. We mutated four positions in the germline T15L that had amino acids infrequently found in other κ-chains. Mutation to the most frequently occurring amino acid at three of the four positions allowed secretion of free L chain, while the combination of two secretion-restoring mutations was synergistic. Coexpression of secretion-restored mutant L chains with the secretion-defective mutant H chains rescued secretion of the assembled H2L2 complex, suggesting that during somatic hypermutation in vivo, deleterious mutations at the H chain may be compensated by mutations on the L chain. To our knowledge, this is the first example of mutations in IgL chains that are able to restore secretion-defective H chains to secretion competence in mammalian cells.

show abstract

Inhibition of immunoglobulin folding and secretion by dominant negative BiP ATPase mutants.

Cited by 144 publications

References 39 publications

BAP, a Mammalian BiP-associated Protein, Is a Nucleotide Exchange Factor That Regulates the ATPase Activity of BiP

BAP, a Mammalian BiP-associated Protein, Is a Nucleotide Exchange Factor That Regulates the ATPase Activity of BiP

The Mammalian Hsp40 ERdj3 Requires Its Hsp70 Interaction and Substrate-binding Properties to Complement Various Yeast Hsp40-dependent Functions

Restoration of Ig Secretion: Mutation of Germline-Encoded Residues in T15L Chains Leads to Secretion of Free Light Chains and Assembled Antibody Complexes Bearing Secretion-Impaired Heavy Chains

Contact Info

Product

Resources

About