Location and character of keratinocyte muscarinic acetylcholine receptors

Oct. 28/Concurrent

Session 5 - Keratinocyte Biology and Biochemistry

053

056

DESMOGLEIN-I CONTENT IN THE STRATUM CORNEUM INVOLVED IN THEIR ADHESIVE PROPERTIES Takashi Kitahara. Hirovuki Shinta and Genii Imokawa.

IS DIRECTLY

Kao Biological Science Laboratories, Tochigi. Japan Aberration in cohesive components, such as stratum corneum lipid and desmosomal proteins, is associated with altered desquamation. However. the relationshio between the maonitude of intercellular adhesion’and quantitative’changes in cohesive components remains obscure. In order to understand biochemical event in desquamatory process which leads to an alteration of adhesion in the stratum corneum, we quantified a desmosomal membrane core components, Desmoalein-1 . in stratum corneum layer (SC layer) exfoliated from the surface-of the skin by cyanoacrylate r&&in relation to altered adhesive properties as seen in the normal and UVB-exposed skin. In the normal skin, Desmoglein-1 showed significant regional variation with the sole containing several times larger amount than the upper arm. On the other hand, the sole displayed the higher magnitude of cohesion between the stripped SC layer than the upper arm. In UVB-induced flaky skin, the number of the stripped SC layer increased in a UVB dosedependent manner, with elevated Desmoglein-1 content per mg extracted proteins. These results indicate that changes in Desmoglein-1 content are associated with an altered intercellular adhesion in normal as well as UVB-exposed skin, suggesting that desmosomal proteins play a role in augmented adhesion as a cohesive component in the stratum corneum.

054

055 A COMPREHENSIVE PROTEIN DATABASE APPROACH TO THE STUDY OF PSORIASIS: TOWARDS MOLECULAR DIAGNOSTICS. Pcdcr Madsen. Hanne H. Rasmussen. Henrik Leffers. Evdfinnur Olsen. Kurt Dcieaard. Mortc” N~rlsa”. Bent Honor6 and Julio E. C&s. Institute of Medical Biochemistry and Danish Crntre for Human Genome Research. Aarhus University, Aarhus C, Dcnmnrk A frcat deal of rcscarch is currcnlly being devoted to the study of psoriasis. P hypcrprolifuativc dwasc that is accompanied by inflammation and infiltration oi leukocytes AL prcccnt. relntivcly littlc is know” about the molecular mechanisms underlying this disease. and I” gcncral, most stud”% have hee” directed towards the mvolvcmcnt of cytokmcs. growth factors and denvauvzs of arachldonic acid. Using a two-dmxnsmnal gel protci” datahasc approach, we have identified a group of low molecular wcifht proteins that are highly up-regulated I” unfracuonated non-cultured Pronair kerwnocytes and that may he related to the pathophyszology of the dwase. Thew include. pwnasn”. PA-FABP (psormsis assocmlrd fatty acid handing protr~“), MRP R: MRP 14; Ihc intcrlcuknn-I rcccptor antagonist: cystati” A, kcratin 16 and xvcml unknown proictns. Psoriasi” and PA-FABP have ken cloned by using ~~lleodroxyrlhonuciaotidcs derived from hacktranslated peptidc microsrquenccs ohtalncd from two-dxmensional gslelectrophoresn purified protein. We have also cloned il Irctin~like protein that IS moderately down-regulated I” psoriatic kcratmocytcs. Pson.wn and PA-FABP are strongly uprzgulatcd at the w.nscr~ptional IwcI in psonanc kcratrnocyta Two unknown protans called phorholi” and 2 that 3~ upregulated I” psoriallc krratlnocytes, can he lnducrd by PMA (12.myristate-17. ux,tcI. sugge\ti”g that thcsc proteins may hr involved I” ,hr PKC pathway. En,xcwon of mo\t of these proteins can hc Induced r” normal kerarinocytes by

I

addltmn p\oriauc

fetal call vxum kcratinocyer

to medium

and thereby

- at least in part - rrsrmbling

058 L-36 MAMMALfAN

LACTOSE~SINDING

LECTIN

PROTEIN M.L. Chw E.H. Hamdton. S. A. Feldman’. North Carolma, Chapel Hill, NC; *Bowman Salem. NC. We have described

IS AN EPlTHELlAL

JUNCTION

and E. J. O’Keefe. Unwers~ty of Gray School of Medicine, Wineton

a 37 kGa peg epithehal

juncoon

protel”.

probably

an

adherens junction protein, which IS umque because of its hmltafion to suprabasal cells and 2% restnction. in the case of stratifled ep~thehum, pramardy to oral epnhelium. cDNA clonmg from a pug tongue cDNA library ylelded a 1 .I kb full length clone codmg for a 324 emino acid protein whfch on homology search was found to be 71% identtcaf with a ret mtestina, lecti” of unknown function know” es L-36.

It was not clear whether

the p!g protem was functionally

slmdar

horn&g or a closely related protem wth a different funcnon. Attempts to demonstrate the protem I” human and ret epithellum and in cultured pug ore, keratlnocytes with polyclonal antubady to the pig protein were unsuccessful. Smce the ret protel” is present I” mtestme, we stained cultured human colon carcinoma cells with antibody to the pig protein. Stmmng revealed typical ionctional stammq verv similar I” locatm” to E-cadherm fuvomorul~n~, an adherens

_

junction protem. Furthermore, reverse transcriptase-PCR wng human tongue mRNA o, human colon ce”zmome cells welded cDNAs of 290 sod 590 bp respect,vely ~8th SO %,de”tlty I” deduced amino x&d sequence to the rat and p,g protems. Smce both pug and human protems have the typical appearance of ,unctlo” junct~o” lectm.

proteins by nmmunofluorescence: protem and that the mammahan

we conclude that the L-36 protein junctmn provan IS a lactose-bmding

1s a