An Hsp70-like protein in the ER: identity with the 78 kd glucose-regulated protein and immunoglobulin heavy chain binding protein.
We have characterized a cDNA clone that encodes a protein related to the 70 kd heat shock protein, but is expressed in normal rat liver. This protein has a hydrophobic leader and is secreted into the endoplasmic reticulum. We show that it is identical with two previously described proteins: GRP78, whose synthesis is induced by glucose starvation, and BiP, which is found bound to immunoglobulin heavy chains in pre-B cells. This protein, which is abundant in antibody-secreting cells, can be released from heavy chains by ATP, a reaction analogous to the release of hsp70 from heat shocked nuclear structures. We propose a specific role for this protein in the assembly of secreted and membrane-bound proteins.
D000255:Adenosine Triphosphate / Q000502:physiology; D000818:Animals; D000921:Antibody-Producing Cells / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism*; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins / Q000302:isolation & purification* / Q000378:metabolism; D007143:Immunoglobulin Heavy Chains / Q000302:isolation & purification* / Q000378:metabolism; D008565:Membrane Proteins / Q000302:isolation & purification* / Q000378:metabolism; D008970:Molecular Weight; D021382:Protein Sorting Signals / Q000502:physiology; D051381:Rats
D002352:Carrier Proteins; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D007143:Immunoglobulin Heavy Chains; D008565:Membrane Proteins; D021382:Protein Sorting Signals; C018551:glucose-regulated proteins; D000255:Adenosine Triphosphate; D004247:DNA