A role for a 70-kilodalton heat shock protein in lysosomal degradation of intracellular proteins.
A 73-kilodalton (kD) intracellular protein was found to bind to peptide regions that target intracellular proteins for lysosomal degradation in response to serum withdrawal. This protein cross-reacted with a monoclonal antibody raised to a member of the 70-kD heat shock protein (hsp70) family, and sequences of two internal peptides of the 73-kD protein confirm that it is a member of this family. In response to serum withdrawal, the intracellular concentration of the 73-kD protein increased severalfold. In the presence of adenosine 5'-triphosphate (ATP) and MgCl2, the 73-kD protein enhanced protein degradation in two different cell-free assays for lysosomal proteolysis.
Chiang
H L
HL
Department of Physiology, Tufts University School of Medicine, Boston, MA 02111.
Terlecky
S R
SR
Plant
C P
CP
Dice
J F
JF
D000595:Amino Acid Sequence; D000818:Animals; D002478:Cells, Cultured; D006360:Heat-Shock Proteins / Q000235:genetics / Q000502:physiology*; D015151:Immunoblotting; D008247:Lysosomes / Q000378:metabolism*; D008969:Molecular Sequence Data; D051381:Rats; D012259:Ribonuclease, Pancreatic / Q000235:genetics / Q000378:metabolism*; D012689:Sequence Homology, Nucleic Acid
D006360:Heat-Shock Proteins; D012259:Ribonuclease, Pancreatic