The vitamin D receptor mediates rapid changes in muscle protein tyrosine phosphorylation induced by 1,25(OH)(2)D(3).
It has been recently shown that the fast non-genomic responses of 1,25(OH)(2)-vitamin D(3) [1,25(OH)(2)D(3)] in skeletal muscle cells involve tyrosine phosphorylation of MAP kinase (ERK1/2), c-Src kinase and the oncoprotein c-myc. In the present work, blockade of vitamin D receptor (VDR) expression (> or =80%) by preincubation of chick embryonic muscle cells with three different antisense oligonucleotides against the VDR mRNA (AS-VDR ODNs) significantly reduced (-94%) 1,25(OH)(2)D(3) stimulation of c-myc tyrosine phosphorylation and inhibited c-Src tyrosine dephosphorylation implying lack of c-Src activation by the hormone. Coimmunoprecipitation experiments revealed that 1,25(OH)(2)D(3) induces the formation of complexes between c-Src and c-myc, in agreement with the above results and previous studies showing hormone-dependent association between c-Src and tyrosine phosphorylated VDR and c-Src mediated c-myc tyrosine phosphorylation. MAPK tyrosine phosphorylation by 1,25(OH)(2)D(3) was affected to a lesser extent (-35%) by transfection with AS-VDR ODNs implying that both VDR-dependent and VDR-independent signalling mediate hormone stimulation of MAPK. These are the first results providing direct evidence on the participation of the VDR in non-genomic 1,25(OH)(2)D(3) signal transduction. Activation of tyrosine phosphorylation cascades through this mechanism may contribute to hormone regulation of muscle growth.
Buitrago
C
C
Departamento de Biología, Bioquímica and Farmacia, Universidad Nacional del Sur., Bahía Blanca, San Juan 670, 8000, Argentina.
Vazquez
G
G
De Boland
A R
AR
Boland
R
R
D000818:Animals; D001483:Base Sequence; D000081247:CSK Tyrosine-Protein Kinase; D002117:Calcitriol / Q000494:pharmacology*; D002478:Cells, Cultured; D002642:Chick Embryo; D004789:Enzyme Activation / Q000187:drug effects; D015870:Gene Expression; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009124:Muscle Proteins / Q000737:chemistry / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000187:drug effects / Q000378:metabolism; D020319:Oligodeoxyribonucleotides, Antisense / Q000235:genetics / Q000494:pharmacology; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000737:chemistry / Q000378:metabolism; D016271:Proto-Oncogene Proteins c-myc / Q000737:chemistry / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D018167:Receptors, Calcitriol / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D014443:Tyrosine / Q000378:metabolism; D019061:src-Family Kinases
D009124:Muscle Proteins; D020319:Oligodeoxyribonucleotides, Antisense; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger; D018167:Receptors, Calcitriol; D014443:Tyrosine; D011505:Protein-Tyrosine Kinases; D000081247:CSK Tyrosine-Protein Kinase; D019061:src-Family Kinases; D020928:Mitogen-Activated Protein Kinases; D002117:Calcitriol