first harmonin_N_like domain (repeat 1) of the long isoform of whirlin, and related domains
This subgroup contains the first of two harmonin_N_like domains of the long isoform of whirlin, and related domains. Whirlin is a postsynaptic density-95/discs-large/ZO-1 (PDZ) domain-containing scaffold protein which binds various components of the Usher protein network of the inner ear and the retina: erythrocyte protein p55, usherin, VlGR1, and myosin XVa. The long isoform of whirlin contains two harmonin_N_like domains, and three PDZ protein-binding domains, PDZ1-3. This first harmonin_N_like domain precedes PDZ1, and is a putative protein-binding module based on its sequence similarity to the N-terminal domain of harmonin. This first harmonin_N_like domain has been assayed for interaction with the cytoplasmic domain of cadherin 23 (a component of the Usher network and an interacting partner of the harmonin N-domain), however no interaction could be detected. The short whirlin isoform, derived from an alternative start ATG, lacks this first harmonin_N_like domain. The short isoform has in common with the long isoform, the second harmonin_N_like domain (designated repeat 2, not present in this subgroup), and PDZ3.
Jiyao W et al.(2023). "The conserved domain database in 2023.",