Heterogeneous nuclear ribonucleoprotein K enhances insulin-induced expression of mitochondrial UCP2 protein.
The uncoupling protein 2, UCP2, is a member of a family of inner mitochondrial membrane ion carriers involved in a host of metabolic processes. UCP2 protein is encoded by nuclear genome, but the protein is found exclusively in the mitochondria. The heterogeneous nuclear ribonucleoprotein K (hnRNPK) is an RNA-binding protein involved in many processes that compose gene expression, including mRNA processing and translation. The yeast three-hybrid screen revealed K protein bound to ucp2 mRNA through sites located in the 3'-untranslated region of the transcript. ucp2 mRNA-K protein complexes were associated with polysome-coated mitochondria. Expression of exogenous K protein augmented the insulin-induced mitochondrial level of UCP2 protein that was not accompanied by a corresponding increase in ucp2 mRNA. These results suggest the insulin stimulates translation of ucp2 mRNA in a process that involves K protein.
Department of Medicine, University of Washington, Seattle, Washington 98195, USA.
Jerzy
J
Ostrowski
Karolina
K
Klimek-Tomczak
Lucjan S
LS
Wyrwicz
Michal
M
Mikula
Daniel S
DS
Schullery
Karol
K
Bomsztyk
D020413:3' Untranslated Regions; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002458:Cell Fractionation; D015870:Gene Expression; D034641:Heterogeneous-Nuclear Ribonucleoprotein K / Q000235:genetics / Q000502:physiology*; D006801:Humans; D007328:Insulin / Q000494:pharmacology*; D007473:Ion Channels; D008114:Liver Neoplasms, Experimental; D026901:Membrane Transport Proteins / Q000235:genetics*; D051379:Mice; D008930:Mitochondria, Liver / Q000737:chemistry*; D024101:Mitochondrial Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D018482:Muscle, Skeletal / Q000737:chemistry; D014176:Protein Biosynthesis / Q000187:drug effects; D012333:RNA, Messenger / Q000737:chemistry / Q000378:metabolism; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012441:Saccharomyces cerevisiae; D016415:Sequence Alignment; D014162:Transfection; D014407:Tumor Cells, Cultured; D020798:Two-Hybrid System Techniques; D000071246:Uncoupling Protein 2
D020413:3' Untranslated Regions; D034641:Heterogeneous-Nuclear Ribonucleoprotein K; D007328:Insulin; D007473:Ion Channels; D026901:Membrane Transport Proteins; D024101:Mitochondrial Proteins; D012333:RNA, Messenger; C000604389:UCP2 protein, human; C000604390:Ucp2 protein, mouse; C000604391:Ucp2 protein, rat; D000071246:Uncoupling Protein 2