PTBP1, RNA recognition motif 1 (IPR035000)

Short name: PTBP1_RRM1

Overlapping homologous superfamilies

Domain relationships


This entry represents the RNA recognition motif 1 (RRM1) of polypyrimidine tract-binding protein 1 (PTBP1).

PTBP1 (also known as PTB) is involved in numerous post-transcriptional steps in gene expression in both the nucleus and cytoplasm. It can act as a negative regulator of alternative splicing and as an activator of translation driven by IRESs (internal ribosome entry segments) [PMID: 22817740]. It contains four RNA recognition motifs (RRM). RRM1 and RRM2 are independent from each other and separated by flexible linkers. By contrast, there is an unusual and conserved interdomain interaction between RRM3 and RRM4. It is widely held that only RRMs 3 and 4 are involved in RNA binding and RRM2 mediates PTB homodimer formation. However, new evidence shows that the RRMs 1 and 2 also contribute substantially to RNA binding. Moreover, PTB may not always dimerize to repress splicing. It is a monomer in solution [PMID: 15341728, PMID: 16179478].

GO terms

Biological Process

No terms assigned in this category.

Molecular Function

GO:0003723 RNA binding

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.