Recruitment of TIP47 to lipid droplets is controlled by the putative hydrophobic cleft.
Adipose differentiation-related protein (ADRP) and TIP47 show sequence similarity, particularly in their N-terminal PAT-1 domain. Under standard culture conditions, ADRP existed in most lipid droplets (LDs), whereas TIP47 was observed only in some LDs and recruited to LDs on treatment with fatty acids. By analyzing deletion mutants, we found that the C-terminal half of TIP47, or more specifically the putative hydrophobic cleft [S.J. Hickenbottom, A.R. Kimmel, C. Londos, J.H. Hurley, Structure of a lipid droplet protein; the PAT family member TIP47, Structure (Camb) 12 (2004) 1199-1207.], was involved in LD targeting and responsiveness to fatty acids. The result contrasted with that observed for ADRP and implied a distinct LD-targeting mechanism for TIP47. Consistent with this, overexpression of Rab18 decreased ADRP, but not TIP47, from LDs, and TIP47 did not displace pre-existing ADRP from LDs. But ADRP may be a factor to control the TIP47 behavior, because TIP47 in LDs increased upon down-regulation of ADRP. The results suggested that the putative hydrophobic cleft is critical for the unique characteristics of TIP47.
Ohsaki
Yuki
Y
Department of Anatomy and Molecular Cell Biology, Nagoya University Graduate School of Medicine, Japan.
Maeda
Takashi
T
Maeda
Mari
M
Tauchi-Sato
Kumi
K
Fujimoto
Toyoshi
T
D000818:Animals; D001665:Binding Sites; D006224:Cricetinae; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D047908:Intracellular Signaling Peptides and Proteins / Q000737:chemistry / Q000378:metabolism*; D050356:Lipid Metabolism / Q000502:physiology*; D008055:Lipids / Q000737:chemistry; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D051379:Mice; D000070780:Perilipin-2; D000070796:Perilipin-3; D011257:Pregnancy Proteins / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D012995:Solubility; D033921:Vesicular Transport Proteins; D020691:rab GTP-Binding Proteins / Q000737:chemistry / Q000378:metabolism*
D004268:DNA-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008055:Lipids; D008565:Membrane Proteins; C000602982:PLIN2 protein, human; C038196:PLIN3 protein, human; D000070780:Perilipin-2; D000070796:Perilipin-3; C000602983:Plin2 protein, mouse; D011257:Pregnancy Proteins; C484168:RAB18 protein, human; D033921:Vesicular Transport Proteins; D020691:rab GTP-Binding Proteins