The membranes of myelinating Schwann cells are joined by tight, gap and adherens junctions, all of which are found in regions of noncompact myelin: the paranodal loops, incisures of Schmidt-Lanterman and mesaxons. Tight junctions help establish polarity in mammalian epithelia by forming a physical barrier that separates apical and basolateral membranes. Pals-associated tight junction protein (PATJ), the human homolog of Drosophila Discs Lost, is differentially localized in myelinating Schwann cells. PATJ associates with Claudin-1, CRB1 (a transmembrane protein that plays a role in epithelial cell polarity and photoreceptor development), and Pals1 (a Lin-7 associated protein). The PATJ/Pals1/CRB1 complex can form a tripartite tight junction in epithelial cells crucial to their integrity.
Function:
PATJ contains multiple PDZ domains. PDZ domains mediate protein-protein interactions, and proteins with multiple PDZ domains often organize multimeric complexes at the plasma membrane. PATJ localizes to tight junctions and to the apical membrane of epithelial cells. A similar protein in Drosophila is a scaffolding protein which tethers several members of a multimeric signaling complex in photoreceptors.
Subunit:
Interacts with ASIC3, KCNJ10, KCNJ15, GRIN2A, GRIN2B, GRIN2C, GRIN2D, NLGN2, MPP7, HTR2A and SLC6A4 (By similarity). Forms a ternary complex with MPP5, CRB1 and CRB3. Interacts with TJP3/ZO-3 and CLDN1/claudin-1. Component of a complex whose core is composed of ARHGAP17, AMOT, MPP5/PALS1, INADL/PATJ and PARD3/PAR3. Directly interacts with HTR4 (By similarity). Interacts (via PDZ domain 8) with WWC1 (via the ADDV motif).
Subcellular Location:
Membrane. Cell junction; tight junction. Apical cell membrane. Note: Localized in the paranodal region of myelinating Schwann cells. Membrane-associated. Localizes to tight junctions in epithelial cells. Also found at the apical plasma membrane.
Tissue Specificity:
Expressed in bladder, testis, ovary, small intestine, colon, heart, skeletal muscle, pancreas and cerebellum in the brain.
Similarity:
Contains 1 L27 domain.
Contains 10 PDZ (DHR) domains.
SWISS:
Q8NI35
Gene ID:
10207
Database links:
Entrez Gene: 424682 Chicken
Entrez Gene: 536993 Cow
Entrez Gene: 479550 Dog
Entrez Gene: 100070486 Horse
Entrez Gene: 10207 Human
Omim: 603199 Human
SwissProt: Q8NI35 Human
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