Immunofluorescence images of PAR proteins in one-cell embryos are shown below.
PAR-2 is a RING finger-containing protein with an ATP binding site at its carboxy terminus, and is enriched at the posterior cortex. (Levitan et al., 1994; Boyd et al., 1996)
PAR-3 is a 138kDa protein with three PDZ domains, and is enriched at the anterior cortex. (Etemad-Moghadam et al., 1995)
Merged image of PAR-2 and PAR-3 signals.
PAR-1 is a serine-threonine kinase that is enriched at the posterior cortex. (Guo and Kemphues, 1995)
PKC-3 is an atypical protein kinase C that is enriched at the anterior cortex.(Tabuse et al., 1998)
Merged image of PKC-3 and PAR-1.
PAR-6 is a 34kDa protein containing a PDZ domain and a PB1 domain and is enriched at the anterior cortex. (Hung and Kemphues, 1999)
PAR-4 is an 80kDa serine threonine kinase with an acidic N-terminal domain. The protein is present in the cytoplasm and at the cortex of the embryo.
(Watts et al., 2000)
PAR-5 is a member of the 14-3-3 family of proteins,
(formerly called FTT-1). The protein is present throughout the cytoplasm of the early embryo. (Morton et al., 2002)
NMY-2 is the heavy chain of cytoplasmic myosin. It becomes asymmetrically distributed in response to the polarity cue from the sperm centrosomes and is required for proper asymmetric distribution of the PAR proteins. (Guo and Kemphues, 1996; Munro et al., 2004)