pfam04885: Stig1 (This model is not part of the current CDD release)
Stigma-specific STIG1-like protein family
This family represents the Stig1 cysteine rich plant protein. The STIG1 gene is developmentally regulated and expressed specifically in the stigmatic secretory zone. The STIG1 family is involved in various plant-specific functions, including the regulation of cell death, promotion of pollen tube growth, and modification of the interface between embryo and endosperm during seed development. Members of the family are typically cysteine-rich proteins that may undergo processing to perform their roles. For instance, a processed peptide of GRI induces cell death dependent on superoxide and salicylic acid, while STIG1 promotes pollen tube growth and binds phosphoinositol lipids, triggering an intracellular reactive oxygen species elevation. The family is also essential for the formation of structures like the embryo sheath and for the normal separation of embryo and endosperm tissues. This region contains three cystein-rich subdomains.
Jiyao W et al.(2023). "The conserved domain database in 2023.",