Regulation of the Axillary Osmidrosis-Associated ABCC11 Protein Stability by N-Linked Glycosylation: Effect of Glucose Condition.
ATP-binding cassette C11 (ABCC11) is a plasma membrane protein involved in the transport of a variety of lipophilic anions. ABCC11 wild-type is responsible for the high-secretion phenotypes in human apocrine glands, such as that of wet-type ear wax, and the risk of axillary osmidrosis. We have previously reported that mature ABCC11 is a glycoprotein containing two N-linked glycans at Asn838 and Asn844. However, little is known about the role of N-linked glycosylation in the regulation of ABCC11 protein. In the current study, we investigated the effects of N-linked glycosylation on the protein level and localization of ABCC11 using polarized Madin-Darby canine kidney II cells. When the N-linked glycosylation in ABCC11-expressing cells was chemically inhibited by tunicamycin treatment, the maturation of ABCC11 was suppressed and its protein level was significantly decreased. Immunoblotting analyses demonstrated that the protein level of the N-linked glycosylation-deficient mutant (N838Q and N844Q: Q838/844) was about half of the ABCC11 wild-type level. Further biochemical studies with the Q838/844 mutant showed that this glycosylation-deficient ABCC11 was degraded faster than wild-type probably due to the enhancement of the MG132-sensitive protein degradation pathway. Moreover, the incubation of ABCC11 wild-type-expressing cells in a low-glucose condition decreased mature, glycosylated ABCC11, compared with the high-glucose condition. On the other hand, the protein level of the Q838/844 mutant was not affected by glucose condition. These results suggest that N-linked glycosylation is important for the protein stability of ABCC11, and physiological alteration in glucose may affect the ABCC11 protein level and ABCC11-related phenotypes in humans, such as axillary osmidrosis.
Department of Pharmacy, The University of Tokyo Hospital, Tokyo, Japan.
Yu
Y
Toyoda
Department of Pharmacy, The University of Tokyo Hospital, Tokyo, Japan.
Tappei
T
Takada
Department of Pharmacy, The University of Tokyo Hospital, Tokyo, Japan.
Hiroshi
H
Miyata
RIKEN Center for Life Science Technology, Yokohama, Japan.
Toshihisa
T
Ishikawa
Department of Pharmacy, The University of Tokyo Hospital, Tokyo, Japan.
Hiroshi
H
Suzuki
D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism*; D019943:Amino Acid Substitution; D000818:Animals; D004285:Dogs; D005947:Glucose / Q000378:metabolism*; D006031:Glycosylation; D057809:HEK293 Cells; D006801:Humans; D061985:Madin Darby Canine Kidney Cells; D020125:Mutation, Missense; D055550:Protein Stability; D059748:Proteolysis
C435500:ABCC11 protein, human; D018528:ATP-Binding Cassette Transporters; D005947:Glucose