Piwi-like protein 2 (PIWIL2, HILI)

Function

• regulates spermatogenesis & primordial germ cell production
• role in meiotic differentiation of spermatocytes
• role in self-renewal of spermatogonial stem cells
• modulates expression of genes involved in
  • stem cell proliferation, including PDGFRB
  • energy metabolism, including SLC2A1
  • cell-cell interaction, including ITGA6, GJA7, THY-1 & CD9
  • germ cell differentiation, including STRA8
• role as a regulatory factor of STAT3/BCL2L1/CCND1 pathway
• inhibits tumor cell growth when repressed
• resricts expression or activity of Long Interspersed Element-1

Structure

• belongs to the argonaute family
• contains 1 PAZ domain
• contains 1 Piwi domain

Compartment

cytoplasm

Alternative splicing

named isoforms=1

Expression

• expressed in adult testis and in most tumors

Pathology

• acts as an oncogene by inhibition of apoptosis & promotion of proliferation in tumors

Comparative biology

• expressed at higher levels in human stem cells relative to other primate stem cells

More general terms

• testis-specific protein
• proto oncogene protein

Database

• UniProt: http://www.uniprot.org/uniprot/Q8TC59.html