Cloning and characterization of DULP, a novel ubiquitin-like molecule from human dendritic cells.
We identified a novel ubiquitin-like molecule DULP from human dendritic cells. DULP contains a domain that shares 26% identity and 34% similarity with ubiquitin, and it possesses the corresponding Ile-44 hydrophobic patch used by mono- or poly-ubiquitin to interact with a ubiquitin-interaction motif (UIM) or ubiquitin-associated domain (UBA). Lysine residue corresponding to 6 of ubiquitin, which is involved in the formation of a multi-ubiquitin chain that can bind proteasomal subunit Rpn10/S5a, is also conserved in its ubiquitin-homology domain. However, DULP does not possess the highly conserved C-terminus Gly-Gly required for ubiquitin conjugation or the Lys-48 required for the formation of polyubiquitin chain to target substrates for degradation, suggesting it might be a novel ubiquitin-domain protein (UDP). DULP was found widely expressed in many cells and the ubiquitin-homology domain was not cleaved. We also confirmed that DULP expression was enriched in the nucleus and much weaker in the cytosol. Besides, we found that overexpression of DULP in 293T cells induced apoptosis, which might not be associated with the mitochondrial or proteasome pathway, with the specific mechanism remaining unclear. Further investigations are needed to identify the precise biological functions of DULP.
Liu
Guo Yan
GY
Institute of Immunology and State Key Laboratory of Medical Immunology, Second Military Medical University, Shanghai 200433, China.
Liu
Shu Xun
SX
Li
Ping
P
Tang
Ling
L
Han
Yan Mei
YM
An
Hua Zhang
HZ
Li
Jiang Yan
JY
Dai
Xian Kun
XK
Li
Nan
N
Cao
Xue Tao
XT
Yu
Yi Zhi
YZ
D000595:Amino Acid Sequence; D017209:Apoptosis; D001483:Base Sequence; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000378:metabolism; D003001:Cloning, Molecular; D003600:Cytosol / Q000378:metabolism; D003713:Dendritic Cells / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D025801:Ubiquitin / Q000737:chemistry / Q000378:metabolism*; D014452:Ubiquitins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
C471042:UBTD2 protein, human; D025801:Ubiquitin; D014452:Ubiquitins