A novel 66-kDa stress protein, p66, associated with the process of cyst formation of Physarum polycephalum is a Physarum homologue of a yeast actin-interacting protein, AIP1.
When exposed to various stresses including heat shock, myxoamoebae, growing haploid cells of Physarum polycephalum, show marked morphological changes and consequently become disk-shaped microcysts. We have found that p66 is induced exclusively in the course of microcyst formation and has an actin-binding activity. In this study, we purified p66 to homogeneity and isolated a p66 cDNA. The deduced protein sequence contained 601 amino acids and showed 31% identity to a yeast actin-interacting protein, AIP1. Northern blot analysis revealed that the amount of p66 mRNA was significantly increased by heat shock in myxoamoebae but not in plasmodia. Thus, p66 seems to be a developmentally-expressed stress protein which regulates the rearrangement of actin organization during microcyst formation in P. polycephalum.
Department of Cell Biology, The Tokyo Metropolitan Institute of Medical Science, Bunkyo-ku, Tokyo, 113-8613, Japan. matsumoto@rinshoken.or.jp
S
S
Matsumoto
M
M
Ogawa
T
T
Kasakura
Y
Y
Shimada
M
M
Mitsui
M
M
Maruya
M
M
Isohata
I
I
Yahara
K
K
Murakami-Murofushi
D000199:Actins / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000032:analysis; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000502:physiology; D006358:Hot Temperature; D008840:Microfilament Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D016839:Physarum polycephalum / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
D000199:Actins; D018076:DNA, Complementary; D005656:Fungal Proteins; D006360:Heat-Shock Proteins; D008840:Microfilament Proteins; D012333:RNA, Messenger; C115237:actin interacting protein 1; C115238:stress protein, 66-kDa (Physarum)