Abstract
LAPTM5 (lysosomal-associated protein multispanning transmembrane 5) is a membrane protein on the intracellular vesicles. We have previously demonstrated that the accumulation of LAPTM5-positive vesicles was closely associated with the programmed cell death occurring during the spontaneous regression of neuroblastomas. Although the accumulation of LAPTM5 protein might occur at the post-translational level, the molecular mechanism has been unclear. Here, we found that the level of LAPTM5 protein is regulated negatively by the degradation through ubiquitination by ITCH, an E3 ubiquitin ligase. ITCH directly binds to the PPxY motif of LAPTM5 via its WW domains and promotes ubiquitination through a HECT-type ligase domain. Overexpression of ITCH led to the degradation of LAPTM5 protein, and conversely, knockdown of ITCH by siRNA resulted in the stabilization of LAPTM5 protein. In addition, the inhibition of ITCH enhanced the cell death occurred by accumulation of LAPTM5 in neuroblastoma cells. These findings suggest that LAPTM5 is a novel substrate in terms of degradation by the ubiquitin ligase ITCH, and this system might act as a negative regulator in the spontaneous regression of neuroblastomas by preventing LAPTM5-mediated cell death.
| Original language | English |
|---|---|
| Pages (from-to) | 44086-44094 |
| Number of pages | 9 |
| Journal | Journal of Biological Chemistry |
| Volume | 286 |
| Issue number | 51 |
| DOIs | |
| Publication status | Published - Dec 23 2011 |
| Externally published | Yes |
Fingerprint
ASJC Scopus subject areas
- Biochemistry
- Cell Biology
- Molecular Biology
Cite this
HECT-type ubiquitin ligase ITCH targets Lysosomal-associated Protein Multispanning Transmembrane 5 (LAPTM5) and prevents LAPTM5-mediated cell death. / Ishihara, Takaya; Inoue, Jun; Kozaki, Ken Ichi; Imoto, Issei; Inazawa, Johji.
In: Journal of Biological Chemistry, Vol. 286, No. 51, 23.12.2011, p. 44086-44094.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - HECT-type ubiquitin ligase ITCH targets Lysosomal-associated Protein Multispanning Transmembrane 5 (LAPTM5) and prevents LAPTM5-mediated cell death
AU - Ishihara, Takaya
AU - Inoue, Jun
AU - Kozaki, Ken Ichi
AU - Imoto, Issei
AU - Inazawa, Johji
PY - 2011/12/23
Y1 - 2011/12/23
N2 - LAPTM5 (lysosomal-associated protein multispanning transmembrane 5) is a membrane protein on the intracellular vesicles. We have previously demonstrated that the accumulation of LAPTM5-positive vesicles was closely associated with the programmed cell death occurring during the spontaneous regression of neuroblastomas. Although the accumulation of LAPTM5 protein might occur at the post-translational level, the molecular mechanism has been unclear. Here, we found that the level of LAPTM5 protein is regulated negatively by the degradation through ubiquitination by ITCH, an E3 ubiquitin ligase. ITCH directly binds to the PPxY motif of LAPTM5 via its WW domains and promotes ubiquitination through a HECT-type ligase domain. Overexpression of ITCH led to the degradation of LAPTM5 protein, and conversely, knockdown of ITCH by siRNA resulted in the stabilization of LAPTM5 protein. In addition, the inhibition of ITCH enhanced the cell death occurred by accumulation of LAPTM5 in neuroblastoma cells. These findings suggest that LAPTM5 is a novel substrate in terms of degradation by the ubiquitin ligase ITCH, and this system might act as a negative regulator in the spontaneous regression of neuroblastomas by preventing LAPTM5-mediated cell death.
AB - LAPTM5 (lysosomal-associated protein multispanning transmembrane 5) is a membrane protein on the intracellular vesicles. We have previously demonstrated that the accumulation of LAPTM5-positive vesicles was closely associated with the programmed cell death occurring during the spontaneous regression of neuroblastomas. Although the accumulation of LAPTM5 protein might occur at the post-translational level, the molecular mechanism has been unclear. Here, we found that the level of LAPTM5 protein is regulated negatively by the degradation through ubiquitination by ITCH, an E3 ubiquitin ligase. ITCH directly binds to the PPxY motif of LAPTM5 via its WW domains and promotes ubiquitination through a HECT-type ligase domain. Overexpression of ITCH led to the degradation of LAPTM5 protein, and conversely, knockdown of ITCH by siRNA resulted in the stabilization of LAPTM5 protein. In addition, the inhibition of ITCH enhanced the cell death occurred by accumulation of LAPTM5 in neuroblastoma cells. These findings suggest that LAPTM5 is a novel substrate in terms of degradation by the ubiquitin ligase ITCH, and this system might act as a negative regulator in the spontaneous regression of neuroblastomas by preventing LAPTM5-mediated cell death.
UR - http://www.scopus.com/inward/record.url?scp=83755162631&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=83755162631&partnerID=8YFLogxK
U2 - 10.1074/jbc.M111.251694
DO - 10.1074/jbc.M111.251694
M3 - Article
VL - 286
SP - 44086
EP - 44094
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 51
ER -