- srbc
Serpentine Receptor, class BC (class B-like)
- srab
Serpentine Receptor, class AB (class A-like)
- pdk
PDK-class protein kinase
- srh
Serpentine Receptor, class H
- srsx
Serpentine Receptor, class SX
- srt
Serpentine Receptor, class T
- srtx
Serpentine Receptor, class TX
- sru
Serpentine Receptor, class U
- srx
Serpentine Receptor, class X