1. Title: Protein Localization Sites


2. Creator and Maintainer:
	     Kenta Nakai
             Institue of Molecular and Cellular Biology
	     Osaka, University
	     1-3 Yamada-oka, Suita 565 Japan
	     nakai@imcb.osaka-u.ac.jp
             http://www.imcb.osaka-u.ac.jp/nakai/psort.html
   Donor: Paul Horton (paulh@cs.berkeley.edu)
   Date:  September, 1996
   See also: ecoli database

3. Past Usage.
Reference: "A Probablistic Classification System for Predicting the Cellular 
           Localization Sites of Proteins", Paul Horton & Kenta Nakai,
           Intelligent Systems in Molecular Biology, 109-115.
	   St. Louis, USA 1996.
Results: 55% for Yeast data with an ad hoc structured
	 probability model. Also similar accuracy for Binary Decision Tree and
	 Bayesian Classifier methods applied by the same authors in
	 unpublished results.

Predicted Attribute: Localization site of protein. ( non-numeric ).


4. The references below describe a predecessor to this dataset and its 
development. They also give results (not cross-validated) for classification 
by a rule-based expert system with that version of the dataset.

Reference: "Expert Sytem for Predicting Protein Localization Sites in 
           Gram-Negative Bacteria", Kenta Nakai & Minoru Kanehisa,  
           PROTEINS: Structure, Function, and Genetics 11:95-110, 1991.

Reference: "A Knowledge Base for Predicting Protein Localization Sites in
	   Eukaryotic Cells", Kenta Nakai & Minoru Kanehisa, 
	   Genomics 14:897-911, 1992.


5. Number of Instances:  1484 for the Yeast dataset.

6. Number of Attributes.
         for Yeast dataset:   9 ( 8 predictive, 1 name )
	     
7. Attribute Information.
  1.  Sequence Name: Accession number for the SWISS-PROT database
  2.  mcg: McGeoch's method for signal sequence recognition.
  3.  gvh: von Heijne's method for signal sequence recognition.
  4.  alm: Score of the ALOM membrane spanning region prediction program.
  5.  mit: Score of discriminant analysis of the amino acid content of
	   the N-terminal region (20 residues long) of mitochondrial and 
           non-mitochondrial proteins.
  6.  erl: Presence of "HDEL" substring (thought to act as a signal for
	   retention in the endoplasmic reticulum lumen). Binary attribute.
  7.  pox: Peroxisomal targeting signal in the C-terminus.
  8.  vac: Score of discriminant analysis of the amino acid content of
           vacuolar and extracellular proteins.
  9.  nuc: Score of discriminant analysis of nuclear localization signals
	   of nuclear and non-nuclear proteins.


8. Missing Attribute Values: None.


9. Class Distribution. The class is the localization site. Please see Nakai &
		       Kanehisa referenced above for more details.
  CYT (cytosolic or cytoskeletal)                    463
  NUC (nuclear)                                      429
  MIT (mitochondrial)                                244
  ME3 (membrane protein, no N-terminal signal)       163
  ME2 (membrane protein, uncleaved signal)            51
  ME1 (membrane protein, cleaved signal)              44
  EXC (extracellular)                                 37
  VAC (vacuolar)                                      30
  POX (peroxisomal)                                   20
  ERL (endoplasmic reticulum lumen)                    5