This gene encodes a member of the heterogeneous family of basic, proline-rich, human salivary glycoproteins. The encoded preproprotein undergoes proteolytic processing to generate one or more mature peptides before secretion from the parotid glands. Multiple alleles of this gene exhibiting variations in the length of the tandem repeats have been identified. The reference genome encodes the 'Small' allele. This gene is located in a cluster of closely related salivary proline-rich proteins on chromosome 12. Alternative splicing results in multiple transcript variants encoding different isoforms that may undergo similar proteolytic processing. [provided by RefSeq, Nov 2015].