home *** CD-ROM | disk | FTP | other *** search
- *************************************
- * Band 4.1 family domain signatures *
- *************************************
-
- A number of cytoskeletal-associated proteins that associate with various
- proteins at the interface between the plasma membrane and the cytoskeleton
- contain a conserved N-terminal domain of about 150 amino-acid residues [1,2].
- The proteins in which such a domain is known to exist are listed below.
-
- - Band 4.1, which links the spectrin-actin cytoskeleton of erythrocytes to
- the plasma membrane. Band 4.1 binds with a high affinity to glycophorin and
- with lower affinity to band 3 protein.
- - Ezrin (cytovillin or p81), a component of the undercoat of the microvilli
- plasma membrane.
- - Moesin [3], which is probably involved in binding major cytoskeletal
- structures to the plasma membrane.
- - Radixin, which seems to play a crucial role in the binding of the barbed
- end of actin filaments to the plasma membrane in the undercoat of the cell-
- to-cell adherens junction (AJ).
- - Talin, which binds with high affinity to vinculin and with low affinity to
- integrins. Talin is a high molecular weight (270 Kd) cytoskeletal protein
- concentrated in regions of cell-substratum contact and, in lymphocytes, of
- cell-cell contacts.
- - Merlin (or Schwannomin) [4]. Defects in this protein are the cause of type
- 2 neurofibromatosis (NF2), a predisposition to tumors of the nervous
- system.
-
- - Protein-tyrosine phosphatases PTP-H1 [5] and PTP-MEG [6]. Structurally
- these two very similar enzymes are composed of a N-terminal band 4.1-like
- domain followed by a central segment of unknown function and a C-terminal
- catalytic domain. They could act at junctions between the membrane and the
- cytoskeleton.
-
- Ezrin, moesin, and radixin are highly related proteins, but the other proteins
- in which this domain is found do not share any region of similarity outside of
- the domain. In band 4.1 this domain is known to be important for the
- interaction with glycophorin, an integral membrane protein.
-
- We have developed two signature patterns for this domain, one is based on the
- conserved positions found at the N-terminal extremity of the domain, the
- second is located in the C-terminal section.
-
- -Consensus pattern: W-L-x(3)-[KR]-x-[LIVM]-x(2)-[QH]-x(0,1)-[LIVMF]-x(6,7)-
- [LIVMF]-x(2,4)-[KR]-F-[FY]-x(2)-[DN]
- -Sequences known to belong to this class detected by the pattern: ALL.
- -Other sequence(s) detected in SWISS-PROT: NONE.
-
- -Consensus pattern: [HY]-x(9)-[DENQST]-[SA]-x(3)-[FY]-[LIVM]-x(2)-A-x(2)-L-
- x(2)-Y-G-[LIVM]-[DENQST]-[LIVMFY]-x(3)-[KR]
- -Sequences known to belong to this class detected by the pattern: ALL.
- -Other sequence(s) detected in SWISS-PROT: NONE.
-
- -Expert(s) to contact by email: Rees J.
- jrees@vax.oxford.ac.uk
-
- -Last update: October 1993 / Pattern and text revised.
-
- [ 1] Rees D.J.G., Ades S.A., Singer S.J., Hynes R.O.
- Nature 347:685-689(1990).
- [ 2] Funayama N., Nagafuchi A., Sato N., Tsukita S., Tsukita S.
- J. Cell Biol. 115:1039-1048(1991).
- [ 3] Lankes W.T., Furthmayr H.
- Proc. Natl. Acad. Sci. U.S.A. 88:8297-8301(1991).
- [ 4] Kinzler K.V., Vogelstein B.
- Nature 363:495-496(1993).
- [ 5] Yang Q., Tonks N.K.
- Proc. Natl. Acad. Sci. U.S.A. 88:5949-5953(1991).
- [ 6] Gu M., York J.D., Warshawsky I., Majerus P.W.
- Proc. Natl. Acad. Sci. U.S.A. 88:5867-5871(1991).
-