Partitioning defective 3 homolog is a protein that in humans is encoded by the PARD3 gene. [5] [6]
PARD proteins, which were first identified in C. elegans, are essential for asymmetric cell division and polarized growth, whereas CDC42 (MIM 116952) mediates the establishment of cell polarity. The CDC42 GTPase, which is controlled by nucleotide exchange factors (GEFs; see MIM 606057) and GTPase-activating proteins (GAPs; see MIM 604980), interacts with a large set of effector proteins that typically contain a CDC42/RAC (MIM 602048)-interactive binding (CRIB) domain.[supplied by OMIM] [6]
PARD3 has been shown to interact with:
The Rho family of GTPases is a family of small signaling G proteins, and is a subfamily of the Ras superfamily. The members of the Rho GTPase family have been shown to regulate many aspects of intracellular actin dynamics, and are found in all eukaryotic kingdoms, including yeasts and some plants. Three members of the family have been studied in detail: Cdc42, Rac1, and RhoA. All G proteins are "molecular switches", and Rho proteins play a role in organelle development, cytoskeletal dynamics, cell movement, and other common cellular functions.
Cell division control protein 42 homolog, also known as Cdc42, is a protein involved in regulation of the cell cycle. It was originally identified in S. cerevisiae (yeast) as a mediator of cell division, and is now known to influence a variety of signaling events and cellular processes in a variety of organisms from yeast to mammals.
Rac1, also known as Ras-related C3 botulinum toxin substrate 1, is a protein found in human cells. It is encoded by the RAC1 gene. This gene can produce a variety of alternatively spliced versions of the Rac1 protein, which appear to carry out different functions.
Transforming protein RhoA, also known as Ras homolog family member A (RhoA), is a small GTPase protein in the Rho family of GTPases that in humans is encoded by the RHOA gene. While the effects of RhoA activity are not all well known, it is primarily associated with cytoskeleton regulation, mostly actin stress fibers formation and actomyosin contractility. It acts upon several effectors. Among them, ROCK1 and DIAPH1 are the best described. RhoA, and the other Rho GTPases, are part of a larger family of related proteins known as the Ras superfamily, a family of proteins involved in the regulation and timing of cell division. RhoA is one of the oldest Rho GTPases, with homologues present in the genomes since 1.5 billion years. As a consequence, RhoA is somehow involved in many cellular processes which emerged throughout evolution. RhoA specifically is regarded as a prominent regulatory factor in other functions such as the regulation of cytoskeletal dynamics, transcription, cell cycle progression and cell transformation.
Protein kinase C iota type is an enzyme that in humans is encoded by the PRKCI gene.
Ras GTPase-activating-like protein IQGAP1 (IQGAP1) also known as p195 is a ubiquitously expressed protein that in humans is encoded by the IQGAP1 gene. IQGAP1 is a scaffold protein involved in regulating various cellular processes ranging from organization of the actin cytoskeleton, transcription, and cellular adhesion to regulating the cell cycle.
Partitioning defective 6 homolog alpha is a protein that in humans is encoded by the PARD6A gene.
Protein ECT2 is a protein that in humans is encoded by the ECT2 gene.
Junctional adhesion molecule C is a protein that in humans is encoded by the JAM3 gene.
Rho-related GTP-binding protein RhoQ is a protein that in humans is encoded by the RHOQ gene.
Junctional adhesion molecule B is a protein that in humans is encoded by the JAM2 gene. JAM2 has also been designated as CD322.
MAP/microtubule affinity-regulating kinase 3 is an enzyme that in humans is encoded by the MARK3 gene.
Cdc42 effector protein 3 is a protein that in humans is encoded by the CDC42EP3 gene.
Cdc42 effector protein 1 is a protein that in humans is encoded by the CDC42EP1 gene.
Partitioning defective 6 homolog beta is a protein that in humans is encoded by the PARD6B gene.
Ras GTPase-activating-like protein IQGAP2 is an enzyme that in humans is encoded by the IQGAP2 gene.
Cdc42 effector protein 4 is a protein that in humans is encoded by the CDC42EP4 gene.
Partitioning defective 3 homolog B is a protein that in humans is encoded by the PARD3B gene.
Cell polarity refers to spatial differences in shape, structure, and function within a cell. Almost all cell types exhibit some form of polarity, which enables them to carry out specialized functions. Classical examples of polarized cells are described below, including epithelial cells with apical-basal polarity, neurons in which signals propagate in one direction from dendrites to axons, and migrating cells. Furthermore, cell polarity is important during many types of asymmetric cell division to set up functional asymmetries between daughter cells.
A junctional adhesion molecule (JAM) is a protein that is a member of the immunoglobulin superfamily, and is expressed in a variety of different tissues, such as leukocytes, platelets, and epithelial and endothelial cells. They have been shown to regulate signal complex assembly on both their cytoplasmic and extracellular domains through interaction with scaffolding that contains a PDZ domain and adjacent cell's receptors, respectively. JAMs adhere to adjacent cells through interactions with integrins LFA-1 and Mac-1, which are contained in leukocyte β2 and α4β1, which is contained in β1. JAMs have many influences on leukocyte-endothelial cell interactions, which are primarily moderated by the integrins discussed above. They interact in their cytoplasmic domain with scaffold proteins that contain a PDZ domain, which are common protein interaction modules that target short amino acid sequences at the C-terminus of proteins, to form tight junctions in both epithelial and endothelial cells as polarity is gained in the cell.