PROSITE documentation PDOC00756
Ly-6 / u-PAR domain signature


A variety of GPI-linked cell-surface glycoproteins are composed of one or more copies of a conserved domain of about 100 amino-acid residues [1,2]. These proteins are:

  • Urokinase plasminogen activator surface receptor u-PAR, which binds to u-PA and is responsible for its proteolysis-independent signal transduction activation effects.
  • The mouse family of Ly-6 T-cell antigens (Ly-6A, -6C, -6E, -6F and -6G).
  • CD59 (MACIF or MIRL), an inhibitor of the complement membrane attack complex action.
  • Herpesvirus saimiri CD59-related protein (gene 15).
  • Mouse thymocyte B cell antigen (ThB).
  • Squid glycoprotein Sgp-2.

U-PAR contains three tandem copies of the domain, while all the others are made up of a single domain.

As shown in the following schematic, this conserved domain contains 10 cysteine residues involved in five disulfide bonds - in u-PAR, the first copy of the domain lacks the fourth disulfide bond.

     +------+     +------------------------+                    +---+
     |      |     |                        |                    |   |
  |                     |                       |              |
  +---------------------+                       +--------------+
'C': conserved cysteine involved in a disulfide bond.

The signature pattern that detects this domain starts towards its extremity and ends at the sixth cysteine.

Last update:

May 2004 / Text revised.


Technical section

PROSITE method (with tools and information) covered by this documentation:

LY6_UPAR, PS00983; Ly-6 / u-PAR domain signature  (PATTERN)


1AuthorsBehrendt N. Ploug M. Patthy L. Houen G. Blasi F. Dano K.
TitleThe ligand-binding domain of the cell surface receptor for urokinase-type plasminogen activator.
SourceJ. Biol. Chem. 266:7842-7847(1991).
PubMed ID1850423

2AuthorsPloug M. Kjalke M. Ronne E. Weidle U. Hoyer-Hansen G. Dano K.
TitleLocalization of the disulfide bonds in the NH2-terminal domain of the cellular receptor for human urokinase-type plasminogen activator. A domain structure belonging to a novel superfamily of glycolipid-anchored membrane proteins.
SourceJ. Biol. Chem. 268:17539-17546(1993).
PubMed ID8394346

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