TCDB is operated by the Saier Lab Bioinformatics Group

9.B.426.  The DUF4175/4401 (DUF4175/4401) Family 

This family consists of proteins that probably have 3 TMSs, sometimes with C-terminal hydrophilic domains, and sometimes with N-terminal hydrophilic domains. A few may have up to 6 TMSs, possiblly due to an internal duplication of the 3 TMS unit.  These proteins may (or may not) be distantly related to protein 9.B.143.4.2 which may have 6 or 8 TMSs.