AJP - Cell Physiology, Vol 255, Issue 6 C816-C821, Copyright © 1988 by American Physiological Society
Increased trehalase expression after glucose limitation of LLC-PK1 clones
Y. Yoneyama and J. E. Lever
Department of Biochemistry and Molecular Biology, University of Texas Medical School, Houston 77225.
Expression of the apical membrane disaccharidase trehalase correlates with
the development of a proximal tubule-specific differentiated phenotype in
the LLC-PK1 cell line derived from renal epithelia. Substitution of
galactose for glucose in the culture medium of confluent cultures resulted
in a significant trehalase induction; a smaller induction was observed
after replacement by fructose, mannose, or the nonmetabolizable sugar
alpha-methyl-D-glucose. Induction was specific for trehalase among other
microvillar hydrolases, reversible after replacement of glucose, and was
increased as a function of decreasing glucose concentration. Stable clonal
cell lines that were inducible by glucose limitation and noninducible
clones were isolated nonselectively. Both types exhibited trehalase
induction after exposure to the differentiation inducer
N,N'-hexamethylene-bis-acetamide (HMBA). These results suggest that
trehalase induction after glucose deprivation occurs by a different
mechanism than that mediated by HMBA.
