FERM domain C-lobe of FERM domain-containing protein 3 and 5 (FRMD3 and 5)
FRMD3 (also called Band 4.1-like protein 4O/4.1O though it is not a true member of that family) is a novel putative tumor suppressor gene that is implicated in the origin and progression of lung cancer. In humans there are 5 isoforms that are produced by alternative splicing. Less is known about FRMD5, though there are 2 isoforms of the human protein are produced by alternative splicing. Both FRMD3 and FRMD5 contain a N-terminal FERM domain, followed by a FERM adjacent (FA) domain, and 4.1 protein C-terminal domain (CTD). The FERM domain has a cloverleaf tripart structure composed of: (1) FERM_N (A-lobe or F1); (2) FERM_M (B-lobe, or F2); and (3) FERM_C (C-lobe or F3). The C-lobe/F3 within the FERM domain is part of the PH domain family. The FERM domain is found in the cytoskeletal-associated proteins such as ezrin, moesin, radixin, 4.1R, and merlin. These proteins provide a link between the membrane and cytoskeleton and are involved in signal transduction pathways. The FERM domain is also found in protein tyrosine phosphatases (PTPs), the tyrosine kinases FAK and JAK, in addition to other proteins involved in signaling. This domain is structurally similar to the PH and PTB domains and consequently is capable of binding to both peptides and phospholipids at different sites.
Feature 1:putative actin binding site 2 [polypeptide binding site]
Evidence:
Comment:ERM and merlin proteins might utilize interaction of the second masking motif with the FERM domain to compete with and suppress the binding of this region to actin
Jiyao W et al.(2023). "The conserved domain database in 2023.",