PMID- 18096610
OWN - NLM
STAT- MEDLINE
DCOM- 20080325
LR  - 20131121
IS  - 0193-1857 (Print)
IS  - 0193-1857 (Linking)
VI  - 294
IP  - 2
DP  - 2008 Feb
TI  - JAM-A is both essential and inhibitory to development of hepatic polarity in 
      WIF-B cells.
PG  - G576-88
AB  - Junctional adhesion molecule (JAM) is involved in tight junction (TJ) formation 
      in epithelial cells. Three JAMs (A, B, and C) are expressed in rat hepatocytes, 
      but only rat JAM-A is present in polarized WIF-B cells, a rat-human hepatic line. 
      We used knockdown (KD) and overexpression in WIF-B cells to determine the role of 
      JAM-A in the development of hepatic polarity. Expression of rat JAM-A short 
      hairpin RNA resulted in approximately 50% KD of JAM-A and substantial loss of 
      hepatic polarity, as measured by the absence of apical cysts formed by adjacent 
      cells and sealed by TJ belts. When inhibitory RNA-resistant human JAM-A (huWT) 
      was expressed in KD cells, hepatic polarity was restored. In contrast, expression 
      of JAM-A that either lacked its PDZ-binding motif (huDeltaC-term) or harbored a 
      point mutation (T273A) did not complement, indicating that multiple sites within 
      JAM-A's cytoplasmic tail are required for the development of hepatic polarity. 
      Overexpression of huWT in normal WIF-B cells unexpectedly blocked WIF-B 
      maturation to the hepatic phenotype, as did expression of three huJAM-A 
      constructs with single point mutations in putative phosphorylation sites. In 
      contrast, huDeltaC-term was without effect, and the T273A mutant only partially 
      blocked maturation. Our results show that JAM-A is essential for the development 
      of polarity in cultured hepatic cells via its possible phosphorylation and 
      recruitment of relevant PDZ proteins and that hepatic polarity is achieved within 
      a narrow range of JAM-A expression levels. Importantly, formation/maintenance of 
      TJs and the apical domain in hepatic cells are linked, unlike simple epithelia.
FAU - Braiterman, Lelita T
AU  - Braiterman LT
AD  - Department of Cell Biology, Johns Hopkins University School of Medicine, 725 N. 
      Wolfe St., Baltimore, MD 21205, USA. lbraite1@jhmi.edu
FAU - Heffernan, Sean
AU  - Heffernan S
FAU - Nyasae, Lydia
AU  - Nyasae L
FAU - Johns, David
AU  - Johns D
FAU - See, Alfred P
AU  - See AP
FAU - Yutzy, Rebeca
AU  - Yutzy R
FAU - McNickle, Allison
AU  - McNickle A
FAU - Herman, Mira
AU  - Herman M
FAU - Sharma, Arun
AU  - Sharma A
FAU - Naik, Ulhas P
AU  - Naik UP
FAU - Hubbard, Ann L
AU  - Hubbard AL
LA  - eng
GR  - DK-063096/DK/NIDDK NIH HHS/United States
GR  - DK-076362/DK/NIDDK NIH HHS/United States
GR  - DK-64388/DK/NIDDK NIH HHS/United States
PT  - Journal Article
PT  - Research Support, N.I.H., Extramural
DEP - 20071220
PL  - United States
TA  - Am J Physiol Gastrointest Liver Physiol
JT  - American journal of physiology. Gastrointestinal and liver physiology
JID - 100901227
RN  - 0 (Cell Adhesion Molecules)
RN  - 0 (F11R protein, human)
RN  - 0 (Immunoglobulins)
RN  - 0 (Receptors, Cell Surface)
RN  - 2ZD004190S (Threonine)
RN  - EC 2.7.11.13 (Protein Kinase C)
SB  - IM
MH  - Amino Acid Sequence
MH  - Animals
MH  - Cell Adhesion Molecules/genetics/*physiology
MH  - Cell Line
MH  - Cell Polarity/*genetics/*physiology
MH  - Cytoplasm/metabolism
MH  - Flow Cytometry
MH  - Fluorescent Antibody Technique
MH  - Hepatocytes/*physiology
MH  - Humans
MH  - Immunoglobulins/genetics/*physiology
MH  - Lentivirus/genetics
MH  - Molecular Sequence Data
MH  - Phosphorylation
MH  - Plasmids/genetics
MH  - Protein Kinase C/metabolism
MH  - Rats
MH  - Receptors, Cell Surface
MH  - Threonine/metabolism
MH  - Transduction, Genetic
EDAT- 2007/12/22 09:00
MHDA- 2008/03/26 09:00
CRDT- 2007/12/22 09:00
PHST- 2007/12/22 09:00 [pubmed]
PHST- 2008/03/26 09:00 [medline]
PHST- 2007/12/22 09:00 [entrez]
AID - 00159.2007 [pii]
AID - 10.1152/ajpgi.00159.2007 [doi]
PST - ppublish
SO  - Am J Physiol Gastrointest Liver Physiol. 2008 Feb;294(2):G576-88. doi: 
      10.1152/ajpgi.00159.2007. Epub 2007 Dec 20.