PMID- 8170472
OWN - NLM
STAT- MEDLINE
DCOM- 19940602
LR  - 20131121
IS  - 0888-8809 (Print)
IS  - 0888-8809 (Linking)
VI  - 8
IP  - 2
DP  - 1994 Feb
TI  - The C-terminal region of the vitamin D receptor is essential to form a complex 
      with a receptor auxiliary factor required for high affinity binding to the 
      vitamin D-responsive element.
PG  - 159-72
AB  - The human vitamin D receptor (hVDR) requires another nuclear protein(s), 
      designated receptor auxiliary factor (RAF), for optimal binding to the vitamin 
      D-responsive element (VDRE). To determine the region in hVDR required to form a 
      heterodimer with RAF on the VDRE, mutant hVDR cDNAs were constructed by 
      site-directed mutagenesis and transfected into COS-7 cells. A truncated hVDR, 
      lacking 25 C-terminal amino acids (delta 403-427), showed complex production in 
      combination with endogenous RAF in COS-7 cells. Complex development was markedly 
      enhanced by adding a rat liver nuclear fraction, which contains RAF activity, or 
      either the alpha or beta form of the retinoid-X receptor, which has been reported 
      to be closely related or identical to RAF. In contrast, either a C-terminal 
      truncation of 46 amino acids (delta 382-427) or single point mutations at 
      lysine-382, methionine-383, glutamine-385, or leucine-390 dramatically reduced 
      the ability of hVDR to heterodimerize with RAF. Binding of 1,25-dihydroxyvitamin 
      D3 [1,25-(OH)2D3] hormone was undetectable in delta 382-427 truncated hVDR, 
      whereas the delta 403-427 mutant hVDR exhibited significant 1,25-(OH)2D3 ligand 
      binding, although the dissociation constant was approximately 10-fold higher than 
      that of the wild-type receptor. Surprisingly, the delta 403-427 mutant hVDR did 
      not mediate measurable transcriptional activation in cotransfection experiments 
      with a VDRE-GH reporter gene construct. These results indicate that hVDR residues 
      between cysteine-403 and serine-427 are required for very high affinity 
      1,25-(OH)2D3 ligand binding and transcriptional activation, but are not involved 
      in heterodimerization. The region of hVDR between lysine-382 and arginine-402, 
      probably the domain containing heptad 9, plays an essential role in the 
      heterodimerization of hVDR with RAF. However, based upon additional point 
      mutagenesis experiments, it is likely that other regions of the hormone-binding 
      domain, such as that including heptad 4 (leucine-325 to leucine-332), also 
      contribute to the protein-protein interactions required for the high affinity, 
      specific binding of hVDR to the VDRE.
FAU - Nakajima, S
AU  - Nakajima S
AD  - Department of Biochemistry, University of Arizona College of Medicine, Tucson 
      85724.
FAU - Hsieh, J C
AU  - Hsieh JC
FAU - MacDonald, P N
AU  - MacDonald PN
FAU - Galligan, M A
AU  - Galligan MA
FAU - Haussler, C A
AU  - Haussler CA
FAU - Whitfield, G K
AU  - Whitfield GK
FAU - Haussler, M R
AU  - Haussler MR
LA  - eng
GR  - AR-15781/AR/NIAMS NIH HHS/United States
GR  - DK-33351/DK/NIDDK NIH HHS/United States
GR  - DK-40372/DK/NIDDK NIH HHS/United States
PT  - Journal Article
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - Mol Endocrinol
JT  - Molecular endocrinology (Baltimore, Md.)
JID - 8801431
RN  - 0 (Nuclear Proteins)
RN  - 0 (Receptors, Calcitriol)
RN  - 0 (nuclear accessory protein, monkey)
RN  - FXC9231JVH (Calcitriol)
SB  - IM
MH  - Amino Acid Sequence
MH  - Animals
MH  - Base Sequence
MH  - Calcitriol/metabolism
MH  - Humans
MH  - Liver
MH  - Molecular Sequence Data
MH  - Mutation/physiology
MH  - Nuclear Proteins/*metabolism
MH  - Point Mutation
MH  - Rats
MH  - Receptors, Calcitriol/chemistry/*metabolism
MH  - Regulatory Sequences, Nucleic Acid/*physiology
MH  - Transcription, Genetic/physiology
EDAT- 1994/02/01 00:00
MHDA- 1994/02/01 00:01
CRDT- 1994/02/01 00:00
PHST- 1994/02/01 00:00 [pubmed]
PHST- 1994/02/01 00:01 [medline]
PHST- 1994/02/01 00:00 [entrez]
AID - 10.1210/mend.8.2.8170472 [doi]
PST - ppublish
SO  - Mol Endocrinol. 1994 Feb;8(2):159-72. doi: 10.1210/mend.8.2.8170472.