How to search for a certain protein:
There are two ways, in order to search for phosphorylation sites of a certain protein:
On the one hand, you can search via IPI identifier (IPI version 3.24) or Swissprot identifier (Uniprot version 9.2). In the case of IPI ids, you do not have to use version numbers.
On the other hand, you can search via sequence (case-insensitive). It is possible to use the entire protein sequence, but also short parts of it (e.g., peptide sequences).

Examples: IPI00107913, IPI00000846, IPI00219301, Q9CZR8, ...

To find the SwissProt number for your protein, click here.