Regulatory nucleotide sequences for a novel Pichia pastoris gene, designated PpSEC10 gene, and the nucleotide sequences and respective amino acid sequences for the secretion leader and the mature Sec10p protein components of the precursor polypeptide encoded by this novel gene are provided. These compositions are useful in methods for expression and secretion of proteins when assembled in proper reading frame, individually or in combination, within a DNA construct that further comprises a nucleotide sequence encoding a protein of interest. Vectors comprising the DNA constructs of the invention can be used to transform a yeast host cell, which can then be cultured to obtain the secreted protein of interest. Kits useful in this method and in methods of detection of the Sec10p protein using antibodies are also disclosed.