Human tra2-beta1 autoregulates its protein concentration by influencing alternative splicing of its pre-mRNA.
HTRA2-BETA1 is an SR-like protein that regulates alternative splice site selection in a concentration-dependent manner. Its proper concentration is important as several pathological states are associated with its change. We investigated the mechanism that controls the cellular HTRA2-BETA1 concentration and found it utilizes a negative feedback loop to regulate the splicing of its exon 2. TRA2-BETA1 binds to four enhancers present in exon 2, which activates its inclusion. Inclusion of exon 2 generates mRNAs that are not translated into proteins. Mutations of exon 2 enhancers demonstrate that TRA2-BETA1 binds a degenerate sequence GHVVGANR, which is found more frequently in exons than in introns. Hyperphosphorylation of TRA2-BETA1 strongly reduces its binding to RNA. Presence of the CLK2 kinase prevents the usage of exons 2 and 3, generating the htra2-beta3 mRNA. The resulting HTRA2-BETA3 protein lacks the first RS domain of HTRA2-BETA1, is expressed in several tissues and has no influence on tra2-beta splice site selection. HTRA2-BETA1 interacting proteins promote exon 2 skipping by sequestering it, which upregulates the HTRA2-BETA1 protein synthesis. We propose that the regulation of the tra2-beta pre-mRNA alternative splicing provides a robust and sensitive molecular sensor that measures the ratio between HTRA2-BETA1 and its interacting proteins.
Stoilov
Peter
P
Institute of Biochemistry, University of Erlangen, Erlangen, Germany.
Daoud
Rosette
R
Nayler
Oliver
O
Stamm
Stefan
S
D017398:Alternative Splicing / Q000235:genetics / Q000502:physiology*; D020816:Amino Acid Motifs; D015153:Blotting, Western; D017931:DNA Primers; D004742:Enhancer Elements, Genetic / Q000235:genetics; D005091:Exons / Q000235:genetics; D005786:Gene Expression Regulation; D006801:Humans; D007106:Immune Sera; D016297:Mutagenesis, Site-Directed; D009154:Mutation / Q000235:genetics; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011505:Protein-Tyrosine Kinases; D012322:RNA Precursors / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000068103:Serine-Arginine Splicing Factors; D014162:Transfection
D017931:DNA Primers; D007106:Immune Sera; D009419:Nerve Tissue Proteins; D012322:RNA Precursors; D016601:RNA-Binding Proteins; C097083:TRA2B protein, human; D000068103:Serine-Arginine Splicing Factors; C066780:Clk dual-specificity kinases; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases